Session EA: CEU Poster Session (2:00-4:00pm)

Helicity Amplitude Composition of Deeply Virtual Compton Scattering Processes and Bethe-Heitler Interference

We provide the general expression of the cross section for deeply virtual exclusive scattering processes discussing in detail its helicity amplitude structure up to twist three accuracy,including kinematic power corrections. The processes analyzed are Deeply Virtual Compton Scattering from both unpolarized and polarized targets, Deeply Virtual Compton Scattering with recoil proton polarization, including their interference with the Bethe-Heitler process. The full azimuthal angular dependence of the cross section is presented. From the various azimuthal angle dependent cross section terms one can deduce the following observables in terms of the aforementioned helicity structures: the absolute cross section, the beam spin asymmetry from an unpolarized proton, the azimuthal asymmetry from a longitudinally/transversely polarized proton and the double-spin asymmetry from a longitudinally/transversely polarized proton.   

Optimizing scintillation light collection in the CENNS-10 liquid argon neutrino-nucleus scattering detector

The CENNS-10 detector is a liquid argon chamber currently running at the SNS at ORNL to observe nuclear recoils from Coherent Elastic Neutrino-Nucleus Scattering (CEvNS) and is one of several technologies implemented by the COHERENT collaboration to measure the CEvNS process' dependence on nuclear size. The observation and measurement of CEvNS is vital to understanding energy propagation in supernovae, a test for physics beyond the standard model, an irreducible background for dark matter direct detection, and a probe into nuclear structure. The functioning of the detector depends on its ability to see light from the neutrino-nuclear scattering, which produces extreme UV radiation. To attain optimum light yield in the detector, several optical measurements and changes were necessary. This poster will discuss these measurements, as well as the future expansion of the liquid argon system.   

Characterization of NaI crystal scintillators for the COHERENT collaboration

The COHERENT project aims to make a first observation of Coherent Elastic Neutrino-Nucleus Scattering (CEvNS) using a set of complimentary detector arrays located at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory. Using NaI scintillators acquired from the DHS-ASP program, we plan to construct a multi-tonne array with the capacity to detect CEvNS even in the presence of moderate background. Such an array would also have sensitivity to charged-current scattering of the SNS' pion Decay-At-Rest neutrinos with potential application to neutrinoless double-beta decay nuclear matrix element calculations. Optimization of the array design requires detailed characterization of the NaI scintillators themselves. We will show results on measurements of the light response and its linearity, as well as the energy resolution as a function of detector voltage. We also measured detector thresholds, dynamic range, and spatial and temporal variation of the detector response.   

Characterization of Two Ton NaI Scintillator

The COHERENT collaboration is dedicated to measuring Coherent Elastic Neutrino-Nucleus Scattering (CE$\nu$NS), an interaction predicted by the standard model that ultimately serves as a background floor for dark matter detection. In the pursuit of observing the $N^2$ scaling predicted, COHERENT is deploying two tons of NaI[Tl] detector to observe CE$\nu$NS recoils of sodium nuclei. Before the two tons of this NaI[Tl] scintillator are deployed, however, all crystals and PMTs must be characterized to understand the individual properties vital to precision in the measurement of CE$\nu$NS. This detector is also expected to allow COHERENT to observe charged current and CE$\nu$NS interactions with $^{127}$I. A standard operating procedure is developed to characterize each detector based on seven properties relevant to precision in the measurement of CE$\nu$NS: energy scale, energy resolution, low-energy light yield non-linearity, decay time energy dependence, position variance, time variance, and background levels. Crystals will be tested and characterized for these properties in the context of a ton-scale NaI[Tl] detector. Preliminary development of the SOP has allowed for greater understanding of optimization methods needed for characterization for the ton scale detector.   

Frequency Domain Multiplexing for Use With NaI[Tl] Detectors

A process used in many forms of signal communication known as multiplexing is adapted for the purpose of combining signals from NaI[Tl] detectors so that fewer digitizer channels can be used to process the signal information from large experiments within the COHERENT collaboration. Each signal is passed through a ringing circuit to modulate it with a characteristic frequency. Information about the signal can be extracted from its amplitude, frequency, and phase. Simulations in LTSpice show that an operational amplifier circuit with a parallel LRC feedback loop can serve as the modulating circuit. Several such circuits can be constructed and housed compactly in a unit, and fed to an inverting, summing amplifier with tunable gain, such that the signals are carried by one cable. The signals are analyzed based on a Fourier transform after being digitized. The results show that the energy, channel, and time of the original interaction can be recovered by this process. In some cases it is possible through filtering and deconvolution to recover the shape of the original signal. The effort is ongoing, but with the design presented it is possible to multiplex 10 detectors into a single digitizer channel.   

Development of Muon Veto System for 185-kg NaI[Ti] Detector

A 185-kg sodium iodide (NaI[Tl]) scintillating detector has been deployed to the basement of the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory in order to observe, and measure, the cross-section of charged-current neutrino interactions on I-137.~ Muons are expected to be the predominate source of background for charge-current interactions at the energy scale of neutrinos produced by the SNS.~ A muon veto system has been developed to reduce background, and will be deployed in the fall.~ Details regarding the hardware and software for the muon veto system will be discussed.   

Simulating the NaI [Tl] Detector for the COHERENT Project

The COHERENT Collaboration plans to deploy a two ton NaI [Tl] detector at the Spallation Neutron Source at the Oak Ridge National Laboratory to measure Coherent Elastic Neutrino-Nucleus Scattering ( CEvNS). We are developing a GEANT4 Monte Carlo based simulation of the whole apparatus to investigate background rates, especially from muons and neutrons, and to characterize the detector. We have performed initial simulations of individual NaI detectors for thecalibration measurements.Simulation results and comparisons to the calibration analysis will be presented.   

Photoproduction of Lambda - Anti-Lambda Particle Pairs.

Photoproduction of baryon-antibaryon pairs is very poorly studied up to the present time. Using the GlueX spectrometer at Jefferson Lab, we have isolated a sample of $\gamma p \to p \bar{\Lambda} \Lambda$ events. This reaction has never previously been seen. With our data sample, we plan to determine the differential photoproduction cross section in the photon energy range from threshold to 11.5 GeV. Comparisons can be made to the simultaneously-measured $\bar{p}p$ photoproduction reaction. In addition, the self-analyzing decay of the hyperons may allow measurement of the hyperon spin polarization and the spin correlations between the hyperon pairs.   

Proton-Antiproton Photoproduction with GlueX at Jefferson Lab

Photoproduction of proton-antiproton pairs has been detected using the GlueX Experiment at Jefferson Lab. This reaction is very poorly understood in the energy range from 4 to 12 GeV, and our study has obtained by far the best statistical precision to date. GlueX uses a polarized real photon beam on a liquid hydrogen target, a solenoidal magnet and drift chambers for tracking charged particles, and scintillator arrays for particle time of flight measurements. Data from the Spring 2016 run have been analyzed to extract about 80,000 fully exclusive events wherein all three final state particles in the reaction $\gamma p \to p \overline{p} p$ were detected. A study of inclusive events wherein either one final-state proton or the final-state antiproton were missing showed that about 10,000,000 events could be reconstructed. Preliminary results show that the reaction mechanism is $t$-channel dominated. Work continues on analyzing the energy and angle dependencies of the reaction.   

Fitting PMT Responses with an Artificial Neural Network

Correctly modeling the low light responce of photodetectors such as photomultiplier tubes (PMT) is crucial for the operation of particle detection relying on the Cherenkov effect. The \textbf{G}as \textbf{R}ing \textbf{I}maging \textbf{Ch}erenkov (GRINCH) in the SuperBigBite Spectrometer (SBS) at Jefferson Lab will rely on an array of 510 29 mm 9125B PMTs. To select the tubes for this array, more than 900 were tested and their low-light response function was fitted. An Artificial Neural Network was defined and trained to extract the relevant PMT parameters without carrying out a detailed fir of the ADC spectrum. These results will be discussed here.   

Modeling the low-light response of photomultiplier tubes

A number of crucial experiments exploring the intricate tomography of protons and neutrons will be carried out in Hall A at Jefferson Lab using the SuperBigBite Spectrometer (SBS), a large acceptance magnetic spectrometer sporting 0.5{\%} momentum and 0.5 mr angular resolution. As part of the standard SBS detector package the \textbf{G}as \textbf{R}ing \textbf{I}maging \textbf{CH}erenkov (GRINCH) detector will help identify particles produced in the experiments. To determine which photomultiplier (PMT) tubes would be used in GRINCH, more than 900 29mm 9125B PMTs were tested. Two models, Bellamy et. al. (NIM A \textbf{339} (1994)) and Dossi et. al. (NIM A \textbf{451} (2000)) were used to fit test data. For the parameters relevant to this study, results from both models were found to be equivalent, and will be discussed here.   

gemcWeb: A Cloud Based Nuclear Physics Simulation Software

gemcWeb allows users to run nuclear physics simulations from the web. Being completely device agnostic, scientists can run simulations from anywhere with an Internet connection. Having a full user system, gemcWeb allows users to revisit and revise their projects, and share configurations and results with collaborators. gemcWeb is based on simulation software gemc, which is based on standard GEant4. gemcWeb requires no C++, gemc, or GEant4 knowledge. Using a simple but powerful GUI allows users to configure their project from geometries and configurations stored on the deployment server. Simulations are then run on the server, with results being posted to the user, and then securely stored. Python based and open-source, the main version of gemcWeb is hosted internally at Jefferson National Labratory and used by the CLAS12 and Electron-Ion Collider Project groups. However, as the software is open-source, and hosted as a GitHub repository, an instance can be deployed on the open web, or any institution's intra-net. An instance can be configured to host experiments specific to an institution, and the code base can be modified by any individual or group.   

Evaluation of Light Collection System for Pion and Kaon Experiments in Hall C at Jefferson Lab

The neutral pion and the kaon are opportune to study the hadron structure through General Parton Distributions, which can be viewed as spatial densities at different momenta of the quarks inside the proton. To study hadron structure with pion or kaon experiments in Hall C at 12 GeV Jefferson Lab, one must analyze the final state neutral pions and kaons and their decay products. For the analysis of these particles, dedicated detectors based on the Cherenkov or scintillation mechanism are used, e.g. the HMS and SHMS aerogel detectors and the PbWO$_{\mathrm{4}}$-based Neutral Particle Spectrometer. A critical part of these detectors is the light collection system. Photomultiplier Tubes (PMTs) have many advantages, however, they are sensitive to magnetic fields and can get damaged by elevated helium levels in the atmosphere. An alternative to PMTs are Avalanche Photodiodes (APDs). APDs are sensitive to background noise, temperature, and radiation. It is thus important to evaluate the benefits of each light collection system and optimize operating conditions to ensure performance over a reasonably long time. I will present a performance study of PMTs exposed to elevated levels of helium and a comparison of APDs as alternatives, as well as new, compact readout methods.   

Minimizing Slope and Kick of Intermediate Bunches for Electron Cooling

Ions in the Jefferson Lab Electron-Ion Collider (JLEIC) will have transverse energy, which limits the beams density. Electron cooling is a process by which a beam of bunched electrons with small transverse kinetic energy is directed along the ion beam with the same velocity. The ions transfer their transverse kinetic energy to the electron bunches, making the ions lose transverse energy. Electron bunches will be supplied by an electron gun. The required current needed to cool the ion beam can be reached by reusing electrons and incorporating RF kicker cavities to supply a pulsed electric field that kicks every 11$^{\mathrm{th}}$ bunch out of the cooling ring. This provides an exact solution that yields zero kick and slope to all intermediate bunches in the cooling ring, which is described by a cosine series with 11 terms. The goal of this project is to determine if solutions exist that are sufficiently close to zero kick and slope, but require less than 4 kicker cavities. The method used to find these solutions is minimizing an objective function through Sequential Least Squares Programming (SLSQP). A Pareto front then demonstrated the average kick vs. average slope when using 1 through 4 kickers.   

Timing and Pulse Shape Discrimination Comparison Against Legacy TDC {\&} QDC and the JLab F250 FADC

The F250 Flash Analog to Digital Convertor (FADC) is a relatively new module used in Data Acquisition Systems (DAQ) at Jefferson Lab. The FADC will replace or supplement older DAQ modules like Time to Digital Converters (TDCs) and Charge Analog to Digital Converters (QDCs). The TDC has a certain known timing resolution and the QDC can integrate a pulse's charge, a feature which can also be used for particle identification between photons and neutrons using pulse shape discrimination (PSD). The focus of this project is developing a test stand to study timing and PSD performance of legacy modules TDC and QDC, and the new F250 FADC. A cosmic telescope was used to extract timing resolution from the TDC and FADC. Through PSD with the QDC and FADC, using a liquid scintillator, we plan to identify photons and neutrons from an americium-beryllium (AmBe) source. Through PSD, we found that the FADC allows for flexible data analysis compared to the QDC. The results indicate that the TDC provides a more accurate measurement of timing resolution than the FADC. This improvement allows for a clear distinction of what module to use when wanting precision of measurement in a DAQ for a cosmic ray telescope.   

Designing a Wien Filter Model with General Particle Tracer

The Continuous Electron Beam Accelerator Facility injector employs a beamline component called a Wien filter which is typically used to select charged particles of a certain velocity. The Wien filter is also used to rotate the polarization of a beam for parity violation experiments. The Wien filter consists of perpendicular electric and magnetic fields. The electric field changes the spin orientation, but also imposes a transverse kick which is compensated for by the magnetic field. The focus of this project was to create a simulation of the Wien filter using General Particle Tracer. The results from these simulations were vetted against machine data to analyze the accuracy of the Wien model. Due to the close agreement between simulation and experiment, the data suggest that the Wien filter model is accurate. The model allows a user to input either the desired electric or magnetic field of the Wien filter along with the beam energy as parameters, and is able to calculate the perpendicular field strength required to keep the beam on axis. The updated model will aid in future diagnostic tests of any beamline component downstream of the Wien filter, and allow users to easily calculate the electric and magnetic fields needed for the filter to function properly.   

Cosmic Ray Tests of Gas Electron Multipliers

The Super Bigbite Spectrometer (SBS) collaboration at Jefferson Laboratory (Jlab) is conducting an experimental program to measure the elastic form factors of nucleons. In association with Jlab, SBS Gas Electron Multipliers (GEMs) have been constructed by the University of Virginia (back trackers) and INFN in Italy (front trackers). The SBS GEMs measuring 40 x 150 cm$^{2}$ (front trackers) and 60 x 200 cm$^{2}$ (back trackers) in surface area are in the process of being conditioned and analyzed for tracking efficiency using cosmic rays in a clean room test lab before further assembly in the fall. These GEMs will be used to track the path of particles scattered off nuclear targets. Scintillators are placed both above and below GEM stacks to trigger a readout. In addition, Hampton University has also constructed a set of 10 x 10 cm$^{2}$ GEMs originally for the OLYMPUS experiment at DESY in Germany, which are now being used for both the MUSE experiment at Paul Scherrer Institute (PSI) in Switzerland and the DarkLight experiment at Jlab's Low Energy Recirculatory Facility (LERF), where they are in the process of being characterized with cosmic rays. This work has been supported by Jefferson Laboratory.   

Particle Identification Using a Ring Imaging Cherenkov Counter

The construction of the Ring Imaging Cherenkov Counter (RICH) at Jefferson Lab aims to significantly enhance the particle identification capabilities of Hall B's CLAS12 spectrometer, particularly with respect to the separation of pions, kaons, and protons in the 3-8 GeV/c momentum range. The RICH functions by detecting a ring of Cherenkov radiation emitted by particles going faster than the speed of light in an aerogel radiator using a vast array of 8x8 multi-anode photomultiplier tubes (MAPMTs). More specifically, using a time-to-digital converter (TDC), each pixel in the 8x8 grid of the MAPMTs will measure whether or not there is a photon hit and will subsequently time-stamp it. My work in this project consisted of implementing parts of the RICH geometry in Geant4 Monte-Carlo (GEMC) simulation software. With the output from the simulation of particles passing through the detector, I built a graphical user interface (GUI) monitoring system that can display the TDC data on the RICH detector. Based on the output of the GEMC simulations, this GUI will show the location and number of hits for each pixel. Once the actual detector is constructed, the monitoring system will be used to record the hits on the detector.   

Modified M20 Beam Position Monitor Testing

Beam position monitors (BPMs) are used to measure lateral beam position. Two pairs of modified wire BPMs are being evaluated for installation into the injector at Jefferson Lab (JLab). The BPMs were coated with a Non-Evaporable Getter (NEG) to aid in pumping at the electron gun, as an ultra-high vacuum is required to protect the gun and to avoid scattering the beam. Beam in the injector has a large diameter, allowing extraction of second moments to give information about beam profile and emittance. The purpose of this project is to determine the effects of NEG coating on the BPMs and to calculate second moments from beam models on the Goubau Line (G-Line). Using the G-Line, scans of the BPMs were taken before and after NEG coating. Each scan produced an electrical field map, which characterizes properties of the BPM, including scale factors and coupling. Second moments were calculated using superposition of previous scan data, and verification of this method was attempted using several beam models. Results show the BPMs responded well to NEG and that measurement of second moments is possible. Once the BPMs are installed, they will enhance gun vacuum and enable monitoring of shape and trajectory of the beam as it exits the electron gun to ensure quality beam for experiments.   

Harmonic Kicker RF Cavity for the Jefferson Lab Electron-Ion Collider EM Simulation, Modification, and Measurements

An important step in the conceptual design for the future Jefferson Lab Electron-Ion Collider (JLEIC) is the development of supporting technologies for the Energy Recovery Linac (ERL) Electron Cooling Facility. The Harmonic Radiofrequency (RF) kicker cavity is one such device that is responsible for switching electron bunches in and out of the Circulator Cooling Ring (CCR) from and to the ERL, which is a critical part of the ion cooling process. Last year, a half scale prototype of the JLEIC harmonic RF kicker model was designed with resonant frequencies to support the summation of 5 odd harmonics (95.26 MHz, 285.78 MHz, 476.30 MHz, 666.82 MHz, and 857.35 MHz); however, the asymmetry of the kicker cavity gives rise to multipole components of the electric field at the electron-beam axis of the cavity. Previous attempts to symmetrize the electric field of this asymmetrical RF cavity have been unsuccessful. The aim of this study is to modify the existing prototype for a uniform electric field across the beam pathway so that the electron bunches will experience nearly zero beam current loading. In addition to this, we have driven the unmodified cavity with the harmonic sum and used the wire stretching method for an analysis of the multipole electric field components.   

Characterization of Multianode Photomultiplier Tubes for a Cherenkov Detector

In the Fall of 2017, Jefferson Lab's CLAS12 (CEBAF Large Acceptance Spectrometer) detector is expecting the addition of a RICH (ring imaging Cherenkov) detector which will allow enhanced particle identification in the momentum range of 3 to 8 GeV/c. RICH detectors measure the velocity of charged particles through the detection of produced Cherenkov radiation and the reconstruction of the angle of emission. The emitted Cherenkov photons are detected by a triangular-shaped grid of 391 multianode photomultiplier tubes (MAPMTs) made by Hamamatsu. The custom readout electronics consist of MAROC (multianode read out chip) boards controlled by FPGA (Field Programmable Gate Array) boards, and adapters used to connect the MAROC boards and MAPMTs. The focus of this project is the characterization of the MAPMTs with the new front end electronics. To perform these tests, a black box setup with a picosecond diode laser was constructed with low and high voltage supplies. A highly automated procedure was developed to acquire data at different combinations of high voltage values, light intensities and readout electronics settings. Future work involves using the collected data in calibration procedures and analyzing that data to resolve the best location for each MAPMT.   

Ring Imaging Cerenkov Detector for CLAS12

The CLAS12 detector at Thomas Jefferson National Accelerator Facility (TJNAF) is undergoing an upgrade. One of the additions to this detector is a Ring Imaging Cherenkov (RICH) detector to improve particle identification in the 3-8 GeV/c momentum range. Approximately 400 multi anode photomultiplier tubes (MAPMTs) will be used to detect Cherenkov Radiation in the single photoelectron spectra (SPS). Detector tests are taking place at Jefferson Lab, while analysis software development is ongoing at Duquesne. I will be summarizing the work done at Duquesne on the Database development and the analysis of the ADC and TDCs for the Hamamatsu Multi-Anode PMTs that are used for Cerenkov light radiation.   

Electrons for Neutrinos: Using Electron Scattering to Develop New Energy Reconstruction for Future Deuterium-Based Neutrino Detectors

Using wide phase-space electron scattering data, we study a novel technique for neutrino energy reconstruction for future neutrino oscillation experiments. Accelerator-based neutrino oscillation experiments require detailed understanding of neutrino-nucleus interactions, which are complicated by the underlying nuclear physics that governs the process. One area of concern is that neutrino energy must be reconstructed event-by-event from the final-state kinematics. In charged-current quasielastic scattering, Fermi motion of nucleons prevents exact energy reconstruction. However, in scattering from deuterium, the momentum of the electron and proton constrain the neutrino energy exactly, offering a new avenue for reducing systematic uncertainties. To test this approach, we analyzed $d(e,e'p)$ data taken with the CLAS detector at Jefferson Lab Hall B and made kinematic selection cuts to obtain quasielastic events. We estimated the remaining inelastic background by using $d(e,e'p\pi^{-})$ events to produce a simulated dataset of events with an undetected $\pi^{-}$. These results demonstrate the feasibility of energy reconstruction in a hypothetical future deuterium-based neutrino detector.   

Background estimation of cosmic-ray induced neutrons in Chooz site water veto tank for possible future Ricochet Deployment

The Ricochet experiment seeks to measure Coherent (neutral-current) Elastic Neutrino-Nucleus Scattering (CE$\nu$NS) using metallic superconducting and germanium semi-conducting detectors with sub-keV thresholds placed near a neutrino source such as the Chooz Nuclear Reactor Complex. In this poster, we present an estimate of the flux of cosmic-ray induced neutrons, which represent an important background in any (CE$\nu$NS) search, based on reconstructed cosmic ray data from the Chooz Site. We have simulated a possible Ricochet deployment at the Chooz site in GEANT4 focusing on the spallation neutrons generated when cosmic rays interact with the water tank veto that would surround our detector. We further simulate and discuss the effectiveness of various shielding configurations for optimizing the background levels for a future Ricochet deployment.   

Development of a 3D-Printed Collimated $^{\mathrm{90}}$Sr Beta Source

Collimated beta particle sources based on $^{\mathrm{90}}$Sr are common calibration sources for atomic decay detector research and development. Due to the short attenuation length of beta particles in matter, the exact geometry of a collimator can drastically change the rate and energy of beta particles exiting the source. 3D printing allows for the quick and easy prototyping of collimators with custom geometries. I will describe the development of a collimator that interfaces directly to a quartz cuvette for the characterization of liquid scintillator cocktails. Future work will include developing a source for the NuDot detector which aims to reconstruct MeV electrons using the separation of Cherenkov and scintillation light.   

Analysis of the polarization observables H and P for $\vec{\gamma} ~ \vec{\mathrm{p}} \rightarrow \pi^{+} \mathrm{n}$

A search is underway to find baryon resonances that have been predicted, but yet remain unobserved. Nucleon resonances, due to their broad energy widths, overlap and must be disentangled in order to be identified. Meson photoproduction observables related to the orientation of the spin of the incoming photon and the spin of the target proton are useful tools to deconvolute the nucleon resonance spectrum. These observables are particularly sensitive to interference between phases of the complex amplitudes. A set of these observables has been measured using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab with linearly-polarized photons having energies from 725 to 2100 MeV with polar angle values of $\cos({\theta_{C.M.}})$ between 1 and -0.8 and transversely-polarized protons in the Jefferson Lab FRozen Spin Target (FROST). By fitting $\pi^{+}$ yields over azimuthal scattering angle, the observables H and P have been extracted. Preliminary results for these observables will be presented and compared with predictions provided by SAID Partial-Wave Analysis Facility.   

Analysis of Quasi-Elastic e-n and e-p Scattering from Deuterium

One of Jefferson Lab's goals is to unravel the quark-gluon structure of nuclei. We will use the ratio, {\it R}, of electron-neutron to electron-proton scattering on deuterium to probe the magnetic form factor of the neutron. We have developed an end-to-end analysis from simulation to extraction of {\it R} in quasi-elastic kinematics for an approved experiment with the CLAS12 detector. We focus on neutrons detected in the CLAS12 calorimeters and protons measured with the CLAS12 forward detector. Events were generated with the Quasi-Elastic Event Generator (QUEEG) and passed through the Monte Carlo code {\it gemc} to simulate the CLAS12 response. These simulated events were reconstructed using the latest CLAS12 Common Tools. We first match the solid angle for {\it e-n} and {\it e-p} events. The electron information is used to predict the path of both a neutron and proton through CLAS12. If both particles interact in CLAS12 the {\it e-n} and {\it e-p} events have the same solid angle. We select QE events by searching for nuclei near the predicted position. An angular cut between the predicted 3-momentum of the nucleon and the measured value, ${\theta_{pq}}$, separates QE and inelastic events. We will show the simulated {\it R} as a function of the four-momentum transfer {\it Q$^2$}.   

Modeling the Nab Experiment Electronics in SPICE

The goal of the Nab experiment is to measure the neutron decay coefficients $a$, the electron-neutrino correlation, as well as $b$, the Fierz interference term to precisely test the Standard Model, as well as probe for Beyond the Standard Model physics. In this experiment, protons from the beta decay of the neutron are guided through a magnetic field into a Silicon detector. Event reconstruction will be achieved via time-of-flight measurement for the proton and direct measurement of the coincident electron energy in highly segmented silicon detectors, so the amplification circuitry needs to preserve fast timing, provide good amplitude resolution, and be packaged in a high-density format. We have designed a SPICE simulation to model the full electronics chain for the Nab experiment in order to understand the contributions of each stage and optimize them for performance. Additionally, analytic solutions to each of the components have been determined where available. We will present a comparison of the output from the SPICE model, analytic solution, and empirically determined data.   

Hybrid Magnetic Shielding

The search for the electric dipole moment of the neutron requires the ambient magnetic field to be on the pT scale which is accomplished with large magnetic shielding rooms. These rooms are fitted with large mu-metal sheets to allow for passive cancellation of background magnetic fields. Active shielding technology cannot uniformly cancel background magnetic fields. These issues can be remedied by combining the methods into a hybrid system. The design used is composed of panels that have an active layer of cancellation between two sheets of mu-metal. The panels form a cube and draw in magnetic fields perpendicular to the surface which can then be reduced using active shielding.   

Analysis of Current-mode Detectors For Resonance Detection In Neutron Optics Time Reversal Symmetry Experiment

One of the most promising explanations for the observed matter-antimatter asymmetry in our universe is the search for new sources of time-reversal (T) symmetry violation. The current amount of violation seen in the kaon and B-meson systems is not sufficient to describe this asymmetry. The Neutron Optics Time Reversal Experiment Collaboration (NOPTREX) is a null test for T violation in polarized neutron transmission through a polarized $^{139}$La target. Due to the high neutron flux needed for this experiment, as well as the ability to effectively subtract background noise, a current-mode neutron detector that can resolve resonances at epithermal energies has been proposed. In order to ascertain if this detector design would meet the requirements for the eventual NOPTREX experiment, prototypical detectors were tested at the NOBORU beam at the Japan Proton Accelerator Research Complex (JPARC) facility. Resonances in In and Ta were measured and the collected data was analyzed. This presentation will describe the analysis process and the efficacy of the detectors will be discussed.   

Analysis of a Current-Mode Detector for the NOPTREX Experiment

Charge, Parity and Time reversal (CPT) symmetries are an important aspect of the Standard Model. One of the outstanding problems in cosmology is the observed matter/antimatter asymmetry seen in the universe, which requires the violation of time reversal symmetry (T). The primary goal of the Neutron Optics Time Reversal Experiment (NOPTREX) is to search for T-violation in polarized neutron transmission through a polarized nuclear target. Preliminary measurements were taken on indium and tantalum resonances at the NOBORU test beam at the Japan Proton Accelerator Research Complex (J-PARC) to test the functionality of a prototype detector for the full experiment. We will discuss the analysis of this data as well as the construction of a secondary experiment to measure the angular correlation $\kappa(J)$ of liquid $^{131}$Xe.   

Temperature Stabilization of the NIFFTE Time Projection Chamber

The Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) is a collaboration measuring nuclear fission cross sections for use in advanced nuclear reactors. A neutron beam incident on targets of Uranium-235, Uranium-238, and Plutonium-239 is used to measure the neutron induced fission cross sections for these isotopes. A Time Projection Chamber (TPC) is used to record these reactions. Significant heat is generated by the readout cards mounted on the TPC, which are cooled by fans. One proposed measurement of the experiment is to compare the cross sections of the target to a proton target of gaseous hydrogen. A constant temperature inside the TPC's pressure vessel is desirable to maintain a constant number of hydrogen target atoms. In addition, a constant temperature minimizes the strain and wrinkles on an amplifying mesh inside the TPC. This poster describes the successful work to develop, build, and install a fan controller using a Raspberry Pi, an Arduino, and a custom circuit board to implement an algorithm called Proportional-Integral-Derivative control.   

Beam Monitor Development for Fermilab E1039

Experiment 1039 at Fermi National Accelerator Laboratory is the approved follow-up experiment to SeaQuest/E906 that had the goal of determining the quark and antiquark distribution within nucleons. The SeaQuest detector was optimized to detect Drell-Yan muon pairs produced by quark-antiquark annihilations that occur when the 120 GeV proton beam impacts a series of targets. E1039 will utilize the same beamline and hardware as SeaQuest, but replaces the unpolarized targets with polarized deuterium and hydrogen targets in order to study the spin contribution of the sea quarks to the collective spin of a nucleon. This measurement is extremely sensitive to asymmetries in the beam profile. Therefore, a new beam luminosity detector is desired to reduce error in the experiment’s primary measurements by providing details of the beam distribution. To test prototypes of this detector, a cosmic test stand was designed and is being built at Abilene Christian University. This stand uses the coincidence of double ended hodoscopes to trigger on the prototype detector. Such a test stand allows us to determine the rates and measure the efficiency of the beam monitor prototype. The development and testing of the beam monitor will be presented.   

Advanced Instrumentation for Molten Salt Flow Measurements at NEXT.

~ The Nuclear Energy eXperiment Testing (NEXT) Lab at Abilene Christian University is building a Molten Salt Loop to help advance the technology of molten salt reactors (MSR). NEXT Lab's aim is to be part of the solution for the world's top challenges by providing safe, clean, and inexpensive energy, clean water and medical Isotopes. Measuring the flow rate of the molten salt in the loop is essential to the operation of a MSR. Unfortunately, there is no flow meter that can operate in the high temperature and corrosive environment of a molten salt. The ultrasonic transit time method is proposed as one way to measure the flow rate of high temperature fluids. Ultrasonic flow meter uses transducers that send and receive acoustic waves and convert them into electrical signals. Initial work presented here focuses on the setup of ultrasonic transducers. This presentation is the characterization of the pipe-fluid system with water as a baseline for future work.   

Optimization and Modification of the SeaQuest Trigger Efficiency Program

The primary purpose E906/SeaQuest is to examine the quark and antiquark distributions within the nucleon. This experiment uses the proton beam from the 120 GeV Fermi National Accelerator Laboratory Main Injector to collide with one of several fixed targets. From the collision, a pair of muons produced by the Drell-Yan process directly probes the nucleon sea antiquarks. The Seaquest spectrometer consists of two focusing magnets, several detectors, and multiple planes of scintillating hodoscopes that helped track and analyze the properties of particles. Hodoscope hits are compared to predetermined hit combinations that would result from a pair of muons that originated in the target. Understanding the trigger efficiency is part of the path to determine the probability of Drell Yan muon pair production in the experiment. Over the years of data taking, the trigger efficiency varied as individual scintillator detection efficiency changed. To accurately determine how the trigger efficiency varied over time, the trigger efficiency program needed to be upgraded to include the effects of inefficiencies in the 284 individual channels in the hodoscope systems. The optimization, modification, and results of the upgraded trigger efficiency program will be presented.   

Remote Monitoring of the Polarized Target’s Control for E1039

The 1039 experiment at FNAL will further our understanding of spin structure by measuring the contribution that sea quarks orbital angular momentum provide to overall nucleon spin. It is accepted that the valence-quarks of nucleons only provide ~30\% of the total nucleon spin. To study the nucleon’s sea quark contribution, E1039 will use the Drell-Yan process by colliding 120 GeV un-polarized beam protons with polarized ammonia targets of hydrogen and deuterium. The asymmetric spin distributions of resulting dimuons will be measured. These asymmetries are sensitive, among other effects, to the orbital angular momentum contribution of the sea quarks. The polarized target requires a multi-stage vacuum pump located near the target. Since access to its present controls will not be possible during running, remote control and monitoring upgrades were required. A secondary control panel was purchased and tested. Information from the programmable logic controller (PLC) must be fed into our data stream to enable remote monitoring and to signal possible alarm conditions. This solution and the program created using explicit TCP/IP messaging to extract data tags from the PLC and log it within our databases will be presented.   

Fermilab E1039 Radiation Studies to Optimize the Experimental Layout

Experiment 1039 at Fermi National Accelerator Lab will use the 120 GeV proton beam from the Main Injector to collide with a polarized target to study the spin structure of the nucleon sea quarks. In particular E1039 will measure the asymmetry in the distribution of the muon pairs produced in the Drell-Yan process. In order to polarize the target of frozen NH3 and ND3 a series of vacuum pumps is needed in the high radiation area near the target. This experiment will use the same spectrometer, beam line, and spill structure as E906 along with same shielding with minor upgrades; therefore measurements made by the Fermilab radiation safety team during SeaQuest run can be used for a radiation study. The measurements of thermoluminescent dosimeter badges, and ion chambers are compared with the MARS simulation of the radiation field in SeaQuest to give the amount of radiation in a particular area outside of the shielding. With these three studies a proposal was made for the best placement of the sensitive electronics that is inside the vacuum pump controller, and to see if more protection is needed. This presentation will cover the process of research and calculations of the radiation study and the proposed best place for the controller electronics.   

Diagnosing Recent Failures In Hodoscope Photomultiplier Tube Bases For FNAL E906

The E906/SeaQuest experiment at Fermi National Accelerator Laboratory is researching the nucleon quark sea in order to provide an accurate determination of the quark and anti-quark distributions within the nucleon. By colliding a 120 GeV proton beam with a set of fixed targets and tracking the dimuons that hit the detectors, it is possible to study the quark/anti-quark interaction that produced the unique dimuon through the Drell-Yan process. However, E906 recently began to experience a number of failures in the Hodoscope Photomultiplier Tube bases in the first two detector stations, which are used in the trigger. It was known that the two most likely causes were radiation damage or overheating. Radiation damage was able to be ruled out when it was found that there was no increase in the number of base failures in high rate areas. It was clear that the heat generated on the custom high rate bases caused several components on the daughter cards to slowly overheat until failure. Using thermal imaging and two temperature probes, it was observed that the components on the daughter cards would reach temperatures over 100 degrees Celcius very quickly during our tests. This presentation will discuss the diagnostic process and summarize how this issue will be prevented in the future.   

Upgrading PhotoMultiplier Tube bases for FNAL E1039

Experiment 1039 at Fermilab National Laboratory is designed to study the spin structure within the nucleon. To effectively work towards a better understanding of the “spin crisis” concerning the quarks and gluons within the nucleon, E1039 will employ a polarized target and a 120 GeV proton beam. The E906/SeaQuest spectrometer will be reused for E1039 since it was designed to measure Drell-Yan events from interactions with quarks in the nucleon sea. The spectrometer consists of several detectors with multiple planes of scintillating hodoscopes, tracking chambers, and two large dipole magnets. An issue arose in the later stages of Experiment 906 regarding the scintillating PhotoMultiplier Tubes(PMTs) high current bases for the first two hodoscope stations. Heat produced in the PMT bases created damage to components on the primary circuit board resulting in failures after years of running. Multiple solutions focused on thermally connecting the daughter cards to the metal shielding pipe while also providing electrical isolation of the high voltages present. Comparisons of thermally conductive adhesive and epoxy were studied with several heat spreaders. This poster will cover the options considered and the chosen solution to the upgrade to the hodoscope PMT bases.   

Measuring beam position for Fermilab experiment E-906/SeaQuest

The SeaQuest experiment at Fermi National Accelerator Laboratory detects pairs of oppositely charged muons (dimuons) produced through interactions of a 120 GeV proton beam with liquid and solid nuclear targets. The detector contains several triggers which select for various muon tracks and one minimum bias trigger which is only correlated with the beam clock. Previous analysis of data from the biased dimuon triggers provided evidence that the proton beam is not positioned at the nominal center of the detector, so this same biased data was analyzed to cross-check previous results and confirm an approximately 1.6 cm beam offset in the y-direction. Then, data from the minimum bias trigger was analyzed to investigate the effects of trigger bias on beam position results. This analysis found a 1.3 $\pm$ 0.01 cm beam offset in the y-direction at the target location and a 1.5 $\pm$ 0.01 cm beam offset at the beam dump. Uncertainties on these values and the significance of these results are still being evaluated.   

Beam Dynamics from Scintillating Fiber Detectors in the Muon g-2 Experiment

The Muon g-2 experiment at Fermilab will determine the muon's anomalous magnetic moment with a projected precision four times higher than previous measurements. Coherent Betatron Oscillations (CBO) contribute a systematic uncertainty to the measurement of the muon spin precession frequency in the storage ring. The scintillating fiber beam monitoring system measures the beam profile as a function of time and observes the betatron and cyclotron oscillations that cause the CBO. The betatron and cyclotron oscillation frequencies are momentum-dependent, leading to damping of the CBO. This poster will present an analysis of these beam dynamics effects measured by Fourier transforms of the data from the fiber beam monitoring system in the commissioning run of June 2017. Understanding and characterizing these effects will allow a reduction of the systematic uncertainty from the CBO.   

Bare Proton Contribution to the $\bar{d} /\bar{u}$ Ratio in the Proton Sea

From perturbative processes, such as gluon splitting, we expect there to be symmetric distributions of $\bar{d}$ and $\bar{u}$ partons in the proton. partons in the proton. However, experiment has shown an excess of $\bar{d}$ over $\bar{u}$. This has been qualitatively explained by the Meson Cloud Model (MCM), in which the non-perturbative processes of proton fluctuations into meson-baryon pairs, allowed by the Heisenberg uncertainty principle, create the flavor asymmetry. The $x$ dependence of $\bar{d}$ and $\bar{u}$ in the nucleon sea is determined from a convolution of meson-baryon splitting functions and the parton distribution functions (pdfs) of the mesons and baryons in the cloud, as well as a contribution from the leading term in the MCM, the ``bare proton." We use a statistical model to calculate pdfs for the hadrons in the cloud, but modify the model for the bare proton in order to avoid double counting. We evolved our distributions in $Q^2$ for comparison to experimental data from the Fermilab E866/NuSea experiment. We present predictions for the $\bar{d}/ \bar{u}$ ratio that is currently being examined by Fermilab’s SeaQuest experiment, E906.   

Monte Carlo Calculations of the Light Flavor Asymmetry in the Proton Sea

The E866/ NuSea experiment has shown a light flavor asymmetry of $\bar{d}$ and $\bar{u}$ in the proton sea. The excess of $\bar{d}$ over $\bar{u}$ can be explained using a statistical model in which the proton is considered a superposition of parton states for which transitions include gluon radiation by quarks and gluons, quark-antiquark pair creation by gluons, and the inverse processes. We use a Monte Carlo simulation to calculate transitions between the states. The advantage of a Monte Carlo simulation is that it is not restricted to detailed balance between states, and that probabilities for different types of transitions can be varied. We use this model to find the probability of each state in the superposition. We extend the model to calculate the momentum distribution for each $n$-parton state, which allows us to determine the $\bar{d}$ and $\bar{u}$ momentum distributions. Our model is evolved in $Q^2$ and compared to E866/ NuSea results. We make predictions for the E906 experiment running at FermiLab.   

Minimising the Residual Field and Field Gradient in a Magnetically Shielded Room for an nEDM experiment at Los Alamos National Laboratory

The LANL neutron Electric Dipole Moment (nEDM) experiment is an effort to set a sensitivity limit of 3.2 x 10$^{\mathrm{-27}} \quad e$ cm on the electric dipole moment of the neutron, an order of magnitude smaller than the current upper limit. This measurement uses Ramsey's method of oscillating magnetic fields. The magnetic field and field gradient have to be low enough to avoid the smearing of the Ramsey fringes and to increase the neutron dephasing time respectively. The experiment is enclosed in a two layer Mu-metal magnetically shielded room (MSR) to null any external magnetic fields from the environment. The MSR is degaussed to sufficiently reduce its residual magnetic field and field gradient. The MSR is designed for residual fields as low as 30 nT. The experiment further requires a field gradient of 1 nT/m or smaller. Here we report on the degaussing procedure and the resulting improvement in the shielding prowess of the MSR.   

Modeling the New UCN source at Los Alamos National Laboratory for the UCNtau Experiment

The Los Alamos Neutron Science Center uses a linear proton accelerator to make an ultracold neutron (UCN) source for use in experiments including the UCNtau and the nEDM experiments. The proton beam strikes a tungsten target, producing free neutrons through spallation. The target is embedded in beryllium and graphite moderators, coupling produced neutrons to a bucket-shaped cold moderator of polyethylene beads at 45K that surrounds a solid deuterium converter, where they are down-scattered to ultracold energies. The UCN source was upgraded over the summer of 2016 and Data taken from the 2016-2017 run cycle shows that continuous running decreases the neutron output caused by layers of deuterium frost building up on the surface of the crystal or in the low temperature part of the UCN guide, and/or other possible changes to the shape, temperature profile or energy content of the deuterium. We have simulated the source deterioration with a simple model for surface roughness and deuterium snow, to understand the expected correlations between the UCN flux and spectrum exiting from the source as snow accumulates. We plan to use the output of our simulation to compare a set of monitor detectors used to establish the output of the flux and to monitor spectral changes important for UCNtau.   

Noble Gas Leak Detector for Use in the SNS Neutron Electric Dipole Moment Experiment

Common practice for leak-checking high vacuum systems uses helium as the probing gas. However, helium may permeate some materials at room temperature, making leak characterization difficult. The experiment to find a permanent electric dipole moment of the neutron (nEDM), to be conducted at Oak Ridge National Laboratories, will employ a large volume of liquid helium housed by such a helium-permeable composite material. It is desirable to construct a leak detector that can employ alternative test gases. The purpose of this experiment is to create a leak detector that can quantify the argon gas flux in a high vacuum environment and interpret this flux as a leak-rate. This apparatus will be used to check the nEDM volumes for leaks at room temperature before cooling down to cryogenic temperatures. Our leak detector uses a residual gas analyzer and a vacuum pumping station to characterize the gas present in an evacuated volume. The introduction of argon gas into the system is interpreted as a leak-rate into the volume. The device has been calibrated with NIST certified calibrated leaks and the machine's sensitivity has been calculated using background gas analysis. As a result of the device construction and software programming, we are able to leak-check composite and polyamide volumes   

Minimizing Environmental Magnetic Field Sources for nEDM

Measurement of the neutron's Electric Dipole Moment (nEDM) could potentially explain the Baryon Asymmetry Problem, and would suggest plausible extensions to the Standard Model. We will attempt to detect the nEDM by measuring the electric-field-dependent neutron precession frequency, which is highly sensitive to magnetic field gradients. In order to produce fields with sufficiently low gradients for our experiment, we eliminate environmental effects by offsetting the ambient field with a Field Compensation System (FCS), then magnetically shielding the reduced field with a Mu-Metal cylinder. We discovered that the strongest environmental effect in our lab came from iron rebar embedded in the floor beneath the proposed experiment location. The large extent and strength of the floor's magnetization made the effect too large to offset with the FCS, forcing us to relocate our apparatus. The floor's magnetic field was mapped with a Hall probe in order to determine the most viable experiment locations. A 3-axis Fluxgate magnetometer was then used to determine the floor field's drop-off and shape at these locations, and a final apparatus position was determined which minimized the floor's effect such that it could be effectively offset and shielded by our experiment.   

Measurement of the Temperature Dependence of the Dielectric Constant of PMMA

The nEDM experiment at Oak Ridge National Laboratory is searching for the electric dipole moment of the neutron to an accuracy of order 10$^{\mathrm{-28}}$ e-cm. In the experiment, ultra cold neutrons are stored in a cell made from PolyMethylMethAcrylate (PMMA) and will be subjected to a 75 kV/cm electric field at 0.4K. In order to calculate the electric field precisely, the dielectric constant of PMMA must be known as a function of temperature. A measurement made last summer (2016) showed that the dielectric constant does change with temperature as measured down to 150K. This summer, we have improved the cryostat and have measured the temperature depend-ence of the dielectric constant down to 77K. These results will be presented.   

Improving Signal Detection using Allan and Theo Variances

Precision measurements often deal with small signals buried within electronic noise. Extracting these signals can be enhanced through digital signal processing. Improving these techniques provide signal to noise ratios. Studies presently performed at the University of Kentucky are utilizing the electro-optic Kerr effect to understand cell charging effects within ultra-cold neutron storage cells. This work is relevant for the neutron electric dipole moment (nEDM) experiment at Oak Ridge National Laboratory. These investigations, and future investigations in general, will benefit from the illustrated improved analysis techniques. This project will showcase various methods for determining the optimum duration that data should be gathered for. Typically, extending the measuring time of an experimental run reduces the averaged noise. However, experiments also encounter drift due to fluctuations which mitigate the benefits of extended data gathering. Through comparing FFT averaging techniques, along with Allan and Theo variance measurements, quantifiable differences in signal detection will be presented.   

An Ultracold Neutron Turntable Switcher for the LANL nEDM Experiment

The goal of a new nEDM experiment at Los Alamos National Laboratory (LANL) is to measure the neutron's electric dipole moment (nEDM) with 1-sigma sensitivity \textasciitilde 3x10-27 e * cm. The experiment will make use of the Ramsey method of separated oscillatory magnetic field pulses to determine the value of the neutron's precession frequency with a strong electric field applied parallel or antiparallel to the holding field. The change in this precession frequency can then be used to calculate the nEDM. ~In the experiment, ultra-cold neutrons (UCNs) travel from the LANL UCN source via guides into a chamber, where the Ramsey magnetic field pulses are applied. The chamber is then unloaded into a detector that measures the polarization of the neutrons. A turntable switcher was constructed to form connections between the source, Ramsey field chamber, and detector. Controlled by a rotary motor, the switcher turns to orient guide pipe sections, first connecting the source to the precession chamber inside a magnetically shielded room, and then to connect the precession chamber to the detector for spin analysis. Discussion of switcher assembly, as well as results of switcher configuration, will be presented.   

Simulation of Light Collection for Neutron Electrical Dipole Moment measurement

nEDM (Neutron Electrical Dipole moment) measurement addresses a critical topic in particle physics and Standard Model, that is CPT violation in neutron electrical dipole moment if detected in which the Time reversal violation is connected to the matter/antimatter imparity of the universe. The neutron electric dipole moment was first measured in 1950 by Smith, Purcell, and Ramsey at the Oak Ridge Reactor - the first intense neutron source. This measurement showed that the neutron was very nearly round (to better than one part in a million). The goal of the nEDM experiment is to further improve the precision of this measurement by another factor of 100. The signal from the experiment is detected by collecting the photons generated when neutron beams were captured by liquid helium 3. The Geant4 simulation project that I participate simulates the process of light collection to improve the design for higher capture efficiency. The simulated geometry includes light source, reflector, wavelength shifting fibers, wavelength shifting TPB and acrylic as in real experiment. The UV photons exiting from Helium go through two wavelength-shifting processes in TPB and fibers to be finally captured.   

Effects of a PID Control System on Electromagnetic Fields in an nEDM Experiment

The Kellogg Radiation Laboratory is currently testing a prototype for an experiment that hopes to identify the electric dipole moment of the neutron. As part of this testing, we have developed a PID (proportional, integral, derivative) feedback system that uses large coils to fix the value of local external magnetic fields, up to linear gradients. PID algorithms compare the current value to a set-point and use the integral and derivative of the field with respect to the set-point to maintain constant fields. We have also developed a method for zeroing linear gradients within the experimental apparatus. In order to determine the performance of the PID algorithm, measurements of both the internal and external fields were obtained with and without the algorithm running, and these results were compared for noise and time stability. We have seen that the PID algorithm can reduce the effect of disturbance to the field by a factor of 10.   

Online Trigger Simulations for the sPHENIX Detector

sPHENIX is a new detector being built to succeed the previous PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC). sPHENIX is designed to measure jets and upsilons with high precision to further our understanding of the Quark Gluon Plasma (QGP). sPHENIX will take data from a variety of collision systems including $p$+$p$, $p$+Au, and Au+Au at $\sqrt{s}$ = 200 GeV. To successfully collect a large sample of data in $p$+$p$ collisions, the capability of an online trigger to select rare events of interest must be understood. In this study, GEANT4 simulations of the detector were used to calculate the efficiency and rejection power of photon, hadron, upsilon, and jet triggers.   

A Magnetic Field Cloak For Charged Particle Beams

The current design for a proposed Electron Ion Collider (EIC) forsees collisions between hadron and electron beams with a momentum ratio of about 12:1, resulting in a majority of particles produced in the hadron-going region. We aim to analyze these particles' momenta using magnetic fields perpendicular to their trajectories, but as their trajectory nears the beam line such fields would interfere with the incoming particle beams. Here, we demonstrate the potential of a magnetic field cloaking device to passively create a field-free tunnel for the beams while minimizing distortions of the applied external field. Such a magnetic field cloak has been fabricated and experimentally shown to shield more than 99\% of the transverse field at 450 mT.   

$\pi^0-\pi^0$ Azimuthal Correlations Comparisons Between PYTHIA and 2008 PHENIX Data

The Muon Piston Calorimeter Extension (MPC-Ex) is housed in front of the Muon Piston Calorimeter (MPC), a sub-detector of PHENIX at RHIC. Using the forward rapidity ($3<\eta<3.8$) arm of the MPC-Ex we can measure the low-$x$ portion of the nuclear wave function and the energy loss in cold nuclear matter using the 2016 $d$+Au run. However, there is no $p$+$p$ baseline for the 2016 $d$+Au run. Using PYTHIA we can create a baseline to compare the 2016 run data. In order to assure the validity of the PYTHIA, we compare the simulation to 2008 $p$+$p$ and $d$+Au $\pi0$-$\pi0$ correlations measured by PHENIX.   

Hadron identification with an Electron Ion Collider based on the sPHENIX experiment

The proposed Electron Ion Collider (EIC) aims to investigate the frontiers of quantum chromodynamics by colliding polarized electrons with ions and polarized protons. In electron-proton collisions, narrow cones of hadrons called jets are formed when a quark or gluon undergoes hadronization. Determining the identity of the leading hadron in these jets is critical to the study of the structure of the proton. The leading hadron is correlated to the flavor of the struck quark, so by identifying the leading hadron, the flavor of the struck quark can be discerned. In this work, we analyze hadron identification at the proposed EIC upgrade of the upcoming sPHENIX experiment at Brookhaven National Laboratory's Relativistic Heavy Ion Collider. The proposed upgrade would require additional tracking, calorimeters, and particle identification systems, one of which is a gas-radiator Ring Imaging Cerenkov (RICH) detector in the hadron-going direction. In this analysis, we wrote a module that identifies the leading hadron using jet information from the GEANT4 simulation of the RICH and ran this through simulated electron-proton collisions. Then, we ran the simulation with different collision energies. Finally, we checked its performance by comparing simulation results with known information.   

Detectors for MUSE

Until recently, it was thought that the proton radius was known with an uncertainty of 1{\%}. However, experiments carried-out at the Paul Scherrer Institute (PSI) involving muonic hydrogen yielded a radius 4{\%} smaller with an uncertainty of .1{\%}, a 7.9$\sigma $ inconsistency. This problem of properly measuring the radius now requires new and different measurements. The Muon Scattering Experiment (MUSE) will thus be the first to utilize elastic muon scattering with sufficient precision to address the proton radius measurement. MUSE will run in PSI's PiM1 beamline, using a stack of GEM chambers and thin scintillation detectors to identify and track the beam particle species in this mixed e, pi, mu beam. Scattered particles will be measured in two arms with ten layers of Straw Tube Tracking (STT) detectors and a double plastic scintillator wall for timing of and triggering on scattered particles. The STT chambers will employ the anti-Proton Annihilations at Darmstadt (PANDA) design. Each straw consists of a thin wire with high voltage surrounded by an aluminized Mylar tube inflated with a mix of Argon and Carbon Dioxide, the ratio of which is important for optimal operation. The Argon gas, ionized by incoming charged particles, releases electrons which attract to the central wire. The CO2 acts as a quencher, taking-up electrons to prevent an unstable avalanche effect. This project will investigate the effects of altering the gas mixture in the STTs on signal size and timing.   

LH$_{\mathrm{2}}$ Target Design {\&} Position Survey Techniques for the MUSE experiment for Precise Proton Radius Measurement

The proton radius puzzle is a currently unresolved problem which has intrigued the scientific community, dealing with a 7$\sigma $ discrepancy between the proton radii determined from muonic hydrogen spectroscopy and electron scattering measurements. The MUon Scattering Experiment (MUSE) aims to resolve this puzzle by performing the first simultaneous elastic scattering measurements of both electrons and muons on the proton, which will allow the comparison of the radii from the two interactions with reduced systematic uncertainties. The data from this experiment is expected to provide the best test of lepton universality to date. The experiment will take place at the Paul Scherrer Institute in Switzerland in 2018. An essential component of the experiment is a liquid hydrogen (LH$_{\mathrm{2}})$ cryotarget system. Our group at the University of Michigan is responsible for the design, fabrication and installation of this system. Here we present our LH$_{\mathrm{2\thinspace }}$target cell design and fabrication techniques for successful operation at 20 K and 1 atm, and our computer vision-based target position survey system which will determine the position of the target, installed inside a vacuum chamber, with 0.01 mm or better precision at the height of the liquid hydrogen target and along the beam direction during the experiment.   

Track Reconstruction and the Proton Radius Puzzle

In 2010, Pohl et al. (Nature 466, 213) measured the proton charge radius to be 0.84184(67) fm using muonic hydrogen spectroscopy. This value differs about 5$\sigma$ from the CODATA proton radius from measurements with electrons. Other experiments with muons and electrons have confirmed the difference and the discrepancy has been termed the “Proton Radius Puzzle.” Currently there are no explanations for the puzzle. The MUon proton Scattering Experiment (MUSE) will make a significant measurement of the proton radius with muon scattering for the first time. The experiment tracks elastic scattering of electrons and muons off of liquid hydrogen. Particle tracks are reconstructed with track fitting software GenFit. Using a simulation of MUSE, GenFit has been determined to be proficient at track reconstruction.   

An Investigation of the Measurement of Jet Shape Dependence on Jet Mass using Pythia.

Jet mass, as measured by the jet reconstruction algorithm, is expected to be constrained by the virtuality of jets resulting in considerable effects on the jet shapes and fragmentation functions. In this poster, we will be showing the jet shape variable dependence on jet mass in Monte Carlo simulations for RHIC energies. This study can be used to optimize the kinematic selection of jets in data, such as the transverse momenta of jet constituents.   

JEWEL predictions for Jet structure modifications at RHIC

RHIC is ideally suited to investigate transport and tomographic properties of the quark gluon plasma in heavy ion collisions using fully reconstructed jets as hard probes. In this poster,~we present predictions for inclusive di-jet and jet structure observables sensitive to jet-medium interactions. This is accomplished by harnessing JEWEL, a Monte Carlo event generator for heavy ion collisions with its updated medium recoil information. With JEWEL's successful record of predictions at the LHC, studying its performance at RHIC energies can precipitate an improved understanding of the jet quenching phenomena.   

Rapidity Dependence of Correlations in Nuclear Collisions in UrQMD

The rapidity dependence of two-particle momentum correlations can be used to probe the viscosity of the liquid produced in heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC). In addition, the differential rapidity structure of these correlations can be used to measure the isotropization time scale $\tau_\pi$ of this liquid [1]. While experimental measurements are constrained to a narrow rapidity window, simulated events allow for the investigation of these correlations in experimentally inaccessible regions. Simulating Au-Au events at $\sqrt{s}=200$ GeV with UrQMD we look for features of momentum correlations that can help constrain theories. Moreover, while earlier theory and measurements focused on correlations of the transverse momentum, $p_t$, the interpretation of these measurements is ambiguous because $p_t$ is not a conserved quantity. We further explore, correlations of the Cartesian components of transverse momenta, $p_x$ and $p_y$ which easier to understand because they are conserved [1,2]. [1] Sean Gavin, George Moschelli, Christopher Zin, Phys. Rev. C 94 (2016) no.2, 024921 [2] Scott Pratt, Soeren Schlichting, Sean Gavin, Phys. Rev. C84, 024909 (2011).   

Analysis of Neutral Pion Helicity Asymmetry with the STAR Detector

The gluon contribution to the proton spin is poorly constrained compared to the quark contribution. To further constrain the gluon contribution, the STAR collaboration at RHIC analyzes the asymmetry in neutral pion ($\pi^0$) production as a function of spin alignment in longitudinally polarized proton beam collisions. These $\pi^0$s mostly decay into photon pairs, some of which are identified in the Endcap Electromagnetic Calorimeter (EEMC) within the STAR detector. The EEMC has a pseudorapidity range of $1 < \eta < 2$ with full azimuthal coverage. The EEMC's Shower Max Detector (SMD) determines the positions of photon showers. A first step in identifying photons is reconstructing clusters of energy in each layer of the SMD. Knowing the position and energy of these photons allows us to reconstruct the $\pi^0$s they decayed from. From these reconstructed $\pi^0$s, a corrected count is determined by fitting signal and background templates from Monte Carlo simulation to the $\pi^0$ candidate invariant mass distributions. We will describe the state of our analysis on the $\sqrt{s} = 510$ GeV dataset from 2012 (integrated luminosity 82 pb$^{-1}$) including cluster identification, Monte Carlo simulation, and data. We will also give a first glimpse of the 2013 dataset (300 pb$^{-1}$).   

Feasibility of Jet Shape Measurements at RHIC

One of the current main questions in nuclear physics is determining the properties of the Quark Gluon Plasma (QGP). One method of studying the properties of the QGP used at the Compact Muon Solenoid (CMS) is measuring the jet shapes, defined as the fractional transverse momentum radial distribution, in a heavy ion collision at a center of mass energy of 2.76 TeV. By comparing how these jets change in the presence of the QGP we can find out more about its properties. This method would be useful to measure the QGP's properties at the Relativistic Heavy Ion Collider (RHIC) at a center of mass energy of 200 GeV. Therefore simulations have been run at RHIC energies and STAR detector specifications to see if jet shape measurements would be feasible.   

Multiplicities of Hadrons Within Jets at STAR

Jet measurements have long been tools used to understand QCD phenomena. There is still much to be learned from the production of hadrons inside of jets. In particular, hadron yields within jets from proton-proton collisions have been proposed as a way to unearth more information on gluon fragmentation functions. In 2011, the STAR experiment at RHIC collected 23 $ pb^{-1} $ of data from proton-proton collisions at $\sqrt{s}=500$ GeV. The jets of most interest for gluon fragmentation functions are those with transverse momentum around 6-15 GeV/c. Large acceptance charged particle tracking and electromagnetic calorimetry make STAR an excellent jet detector. Time-of-flight and specific energy loss in the tracking system allow particle identification on the various types of hadrons within the jets, e.g., distinguishing pions from kaons and protons. An integral part of analyzing the data collected is understanding how the finite resolutions of the various detector subsystems influence the measured jet and hadron kinematics. For this reason, Monte Carlo simulations can be used to track the shifting of the hadron and jet kinematics between the generator level and the detector reconstruction level. The status of this analysis will be presented.   

Development of High Voltage Power Supply Controls for the STAR Experiment at RHIC

The STAR (Solenoidal Tracker at RHIC) experiment at RHIC (Relativistic Heavy Ion Collider) at Brookhaven National Laboratory studies the collisions of various ion species. The large number of channels to be controlled and monitored require an experiment-wide control system for efficient operation. Additionally, the radiation levels require that the user interfaces of the system are located outside the experimental hall. Each sub-detector system at STAR is controlled by software input/output controllers (IOCs). Aging high voltages systems at STAR are being replaced or are having their software updated to run on new processors. The outdated high voltage controls systems occasionally malfunction or require frequent rebooting of the remote hardware. This project aims to design and implement more effective controls software for the Beam-Beam Counter and the Zero Degree Calorimeter high voltage systems in order to mitigate this problem. This work will also be applicable to other subsystems with similar hardware issues.   

Charge dependent correlations relative to the 4th-harmonic event plane in Au+Au collisions at 27 and 39 GeV at RHIC/STAR

In the chiral magnetic effect (CME) [1], an electric current is induced in the presence of a strong magnetic field and a chirality imbalance in the medium created in high-energy nuclear collisions. One corresponding observable for the charge separation across the reaction plane ($\psi$) is the charge dependent two-particle azimuthal correlator, $\gamma$ = < $\cos(\phi_1 + \phi_2 - 2\psi)$ >. However, the $\gamma$ contains both the CME signal and the flow background, complicating the interpretation of the data. In this poster, we investigate the background mechanism with a modified correlator, $\gamma^{II}$ = < $\cos(2\phi_1 + 2\phi_2 - 4\psi)$ >. The $\gamma^{II}$ only contains the background, and reflects the role played by the collective flow in the original $\gamma$ correlator. We will present the STAR data of $\gamma^{II}$ as a function of centrality measured in Au+Au collisions at 27 and 39 GeV. The results will be compared with those obtained by the ALICE experiment at a much higher collision energy, and will also be compared with model calculations. The physics implications will be discussed. [1]D. Kharzeev, Phys. Lett. B 633 (2006) 260.   

Two-particle short-range correlations relative to the reaction plane in Au$+$Au collisions at 200 GeV at RHIC/ STAR

High-energy heavy-ion collisions can create a hot and dense nuclear medium in which local domains could obtain a chirality imbalance. The chirality imbalance, together with a strong magnetic field, can induce an electric charge separation along the magnetic field direction, owing to the chiral magnetic effect (CME) [1]. The $\gamma $ correlator measures the two-particle azimuthal correlations relative to the reaction plane, and provides a probe to the electric charge separation due to the CME. However, the $\gamma $ correlator contains short-range correlations caused by other physics mechanisms, such as quantum effects, Coulomb interaction and resonance decays. In this poster, we decompose the $\gamma $ correlator into two parts, along and across the reaction plane, respectively, and separate the contributions of particle pairs with small relative pseudorapidity (short range). The results will be presented for 200 GeV Au$+$Au collisions, and the physics implications on the short-range background will be discussed.1]D. Kharzeev, Phys. Lett. B 633 (2006) 260   

A Centrality and Event Plane Detector for STAR to Complete the Phase Diagram of Quantum Chromodynamics.

The properties of the nearly perfect liquid, Quark Gluon Plasma (QGP), which filled the universe a microsecond after the Big Bang are studied by colliding heavy-ions at relativistic energies. Our project focuses on building and testing an Event Plane Detector (EPD) for the STAR experiment and analyzing the data collected from collisions. When a minimum ionizing particle hits one of the optically-isolated tiles of this detector, which are made of scintillator plastic, it lights up. The light then travels through a wavelength-shifting fiber embedded in the tile to a clear optical fiber to be detected by silicon photo-multipliers. This detector is an improved version of the Beam-Beam Counter, which is currently at STAR. It will help us measure the centrality and event plane of collisions with more precision. Data collected will aid us in mapping out the transition phase between the QGP and hadronic matter, which evolved into the chemical elements we see today, and in searching for a unique critical point in the phase diagram of Quantum Chromodynamics matter. In 2017, a commissioning run has taken place at RHIC, colliding protons at 510 GeV and gold ions at 54.4 GeV. Some data analysis from one eighth of the EPD that is installed will also be discussed.   

Identifying Jets Using Linear Discriminant Analysis

In order to shed light on the nature of Quark Gluon Plasma (QGP), we utilize the same machine learning principles that are used in image recognition to distinguish among different types of jets, namely jets from PYTHIA-generated proton-proton collisions and quenched jets from heavy ion collisions. We represent jet data as pixelated images, and these jet images are run through a series of preprocessing steps so as to standardize them as much as possible. Next, we use a Linear Discriminant Analysis (LDA) to distinguish between these jet images. The LDA is able to discern quite well among jets that come from different types of collisions.   

Identifying Jets Using Artifical Neural Networks

We investigate particle jet interactions with the Quark Gluon Plasma (QGP) using artificial neural networks modeled on those used in computer image recognition. We create jet images by binning jet particles into pixels and preprocessing every image. We analyzed the jets with a Multi-layered maxout network and a convolutional network. We demonstrate each network's effectiveness in differentiating simulated quenched jets from unquenched jets, and we investigate the method that the network uses to discriminate among different quenched jet simulations. Finally, we develop a greater understanding of the physics behind quenched jets by investigating what the network learnt as well as its effectiveness in differentiating samples.   

J/Psi-meson wavefunction and survival probability in Quark-Gluon Plasma

The time-dependent Schrödinger equation is used to study the formation of the J/Psi in heavy ion collisions and its propagation in Quark-Gluon Plasma (QGP) and in free space. The initial bound state is computed using imaginary-time propagation in a confining potential. An algorithm accommodating both positive and negative energy states has been developed. It can produce all bound states. The QGP is simulated with a confining potential of an expanding, extended asymptotic-freedom region. The time-scales of the J/Psi and QGP formation as well as of the QGP hardonization affect the time-dependence of the J/Psi survival probability in the QGP. This probability is calculated for various J/Psi momenta by projecting the interacting wavefunction onto its freely-propagating counterpart. The staggered-leap frog method is used with special attention paid to the issues of stability and accuracy. The decay of the J/Psi is found to be non-exponential. Connection with experimental results is done by means of cross-section ratios. It is shown that suppression and enhancement are both possible depending on the time-scales.   

Studying the Puzzle of the Pion Nucleon Sigma Term

The pion nucleon sigma term ($\sigma_{\pi N}$) is a fundamental parameter of QCD and is integral in the experimental search for dark matter particles as it is used to calculate the cross section of interactions between potential dark matter candidates and nucleons. Recent calculations of this term from lattice-QCD data disagree with calculations done using phenomenological data. This disparity is large enough to cause concern in the dark matter community as it would change the constraints on their experiments. We investigate one potential source of this disparity by studying the flavor dependence on LQCD data used to calculate $\sigma_{\pi N}$. To calculate $\sigma_{\pi N}$, we study the nucleon mass dependence on the pion mass and implement the Hellmann-Feynman Theorem. Previous calculations only consider LQCD data that accounted for 2 and 3 of the lightest quarks in the quark sea. We extend this study by using new high statistic data that considers 2, 3, and 4 quarks in the quark sea to see if the exclusion of the heavier quarks can account for this disparity.   

Generating Initial Thermal Masses

At temperatures exceeding $T_c \simeq 155$ MeV, ordinary hadrons dissolve into their constituent particles, creating a state of matter called the quark-gluon plasma (QGP). Quark-gluon plasmas, produced in relativistic heavy-ion collisions at temperatures well above $T_c$, rapidly cool and expand as nearly perfect fluids. Below $T_c$, the particles group into color-neutral hadrons in a process called hadronization. As the hadron gas continues to cool, the particles scatter, merge, and decay, until their final state momenta are recorded. Since it is impossible to directly observe a QGP, a series of numerical models are used to infer its properties from the final state data. The focus of the my research was to generate particles with a mass distribution consistent with the spectral function during the simulated hadronization. I first employed a thermal-weighted Lorentzian mass distribution, but the average mass for each particle species was far lower than expected. To limit the skewing effects of the thermal weight, the Lorentzian distribution was modified to include dependencies on the momenta of the interacting particles. Another parameter was incorporated so that the distribution could include dependencies on the angular momenta in the future.   

Machine Vision System for Characterizing the Electric Field for the $^{225}\mathrm{Ra}$ EDM Experiment

If an atom or fundamental particle possesses an electric dipole moment (EDM), that would imply time-reversal violation. At our current capability, if an EDM is detected in such a particle, that would suggest the discovery of beyond the standard model (BSM) physics. The unique structure of $^{225}\mathrm{Ra}$ makes its atomic EDM favorable in the BSM search. An upgraded Ra-EDM apparatus will increase experimental sensitivity and the target electric field of 150kV/cm will more than double the electric field used in previous experiments. To determine the electric field, the potential difference and electrode separation distance must be known. The optical method I have developed is a high-precision, non-invasive technique to measure electrode separation without making contact with the sensitive electrode surfaces. A digital camera utilizes a bi-telecentric lens to reduce parallax error and produce constant magnification throughout the optical system, regardless of object distance. A monochrome LED backlight enhances sharpness of the electrode profile, reducing uncertainty in edge determination and gap width. A program utilizing an edge detection algorithm allows precise, repeatable measurement of the gap width to within 1\% and measurement of the relative angle of the electrodes.   

Comprehensive Parameterization of the p-Meson Spectral Function in Hot and Dense Matter

The goal of this research is to study how hadronic matter transitions into quark-gluon plasma. This transition is believed to have occurred in the early universe about 10 microseconds after the big bang. In particular, this transition created more than 95\% of the visible mass in the universe, and confined quarks and gluons into hadrons. Hot nuclear matter can be recreated in the laboratory by colliding heavy atomic nuclei at very high energies. This transition into the quark-gluon plasma can be probed by analyzing the invariant mass distributions of $\rho$-mesons. The $\rho$-meson was chosen because it decays into dilepton pairs, e.g. or . Dilepton pairs are a preferred observable because they do not interact through the strong nuclear force inside the strongly interacting fireball, therefore ρ-mesons decay into dileptons in the medium and can be measured during heavy ion collisions. In this project, we developed a parameterization of this process which will help to describe quark-gluon plasma which filled the early universe.   

Toward Microscopic Equations of State for Core-Collapse Supernovae from Chiral Effective Field Theory

Chiral effective field theory provides a modern framework for understanding the structure and dynamics of nuclear many-body systems. Recent works have had much success in applying the theory to describe the ground- and excited-state properties of light and medium-mass atomic nuclei when combined with ab initio numerical techniques. Our aim is to extend the application of chiral effective field theory to describe the nuclear equation of state required for supercomputer simulations of core-collapse supernovae. Given the large range of densities, temperatures, and proton fractions probed during stellar core collapse, microscopic calculations of the equation of state require large computational resources on the order of one million CPU hours. We investigate the use of graphics processing units (GPUs) to significantly reduce the computational cost of these calculations, which will enable a more accurate and precise description of this important input to numerical astrophysical simulations.   

Calibration of a Fusion Experiment to Investigate the Nuclear Caloric Curve

In order to investigate the nuclear equation of state (EoS), the relation between two thermodynamic quantities can be examined. The correlation between the temperature and excitation energy of a nucleus, also known as the caloric curve, has been previously observed in peripheral heavy-ion collisions to exhibit a dependence on the neutron-proton asymmetry. To further investigate this result, fusion reactions (78Kr $+$ 12C and 86Kr $+$ 12C) were measured; the beam energy was varied in the range 15-35 MeV/u in order to vary the excitation energy. The light charged particles (LCPs) evaporated from the compound nucleus were measured in the Si-CsI(TI)/PD detector array FAUST (Forward Array Using Silicon Technology). The LCPs carry information about the temperature. The calibration of FAUST will be described in this presentation. The silicon detectors have resistive surfaces in perpendicular directions to allow position measurement of the LCP's to better than 200um. The resistive nature requires a position-dependent correction to the energy calibration to take full advantage of the energy resolution. The momentum is calculated from the energy of these particles, and their position on the detectors. A parameterized formula based on the Bethe-Bloch equation was used to straighten the particle identification (PID) lines measured with the dE-E technique. The energy calibration of the CsI detectors is based on the silicon detector energy calibration and the PID. A precision slotted mask enables the relative positions of the detectors to be determined.   

Characterization of ParTI Phoswiches Using Charged Pion Beams

The Partial Truncated Icosahedron (ParTI) detector array consists of 15 phoswiches. Each phoswich is made of two scintillating components -- a thallium-doped cesium iodide (CsI(Tl)) crystal and an EJ-212 scintillating plastic -- coupled to a photomultiplier tube. Both materials have different scintillation times and are sensitive to both charged and neutral particles. The type of particle and amount of energy deposited determine the shape of the scintillation pulse as a function of time. By integrating the fast and slow signals of the scintillation pulses, a ``Fast vs. Slow Integration'' plot can be created that produces particle identification lines based on the energy deposited in the scintillating materials. Four of these phoswiches were taken to the Paul Scherrer Institute (PSI) in Switzerland where $\pi +$, $\pi $-, and proton beams were scattered onto the phoswiches to demonstrate their particle identification (PID) capabilities. Using digitizers to record the detector response waveforms, pions can also be identified by the characteristic decay pulse of the muon daughters.   

Particle Induced X-Ray Emission experiment using the K150 3.6 MeV proton beam at TAMU Cyclotron Institute

Particle Induced X-Ray Emission (PIXE) is a non-destructive analytical technique that is used for various tasks, such as elemental composition. The x-rays are emitted when electrons transition from higher to lower energy levels, causing vacancies in the atom's electron configuration. The overall goals of this research are to successfully set up a PIXE experiment and to obtain elemental concentrations for various samples, using the K150 proton beam in the Cyclotron Institute at Texas A&M University. The x-rays produced are unique to each element and analyzed with reference to their known energies. The setup consists of 3 different detectors, providing a wide range of energies: XR-100T CdTe$\gamma $/X-Ray, XR-100T/CR Si and XR-100SDD. Accelerating 3.6 MeV protons from the K150 and using PIXE, we determine concentrations from the NaCl samples provided by the Chemical Engineering Department. The concentrations for each element found in the NaCl thin films are obtained and analyzed through the software, GUPIXWIN.   

Production of Radioactive Beams on the Proton Dripline Using MARS at Texas A\&M

Exotic nuclei near the proton dripline are of interest for research in nuclear astrophysics, especially in the study of the r-p process. A ${}^{58}$Ni on Ni reaction at higher energies has been shown to successfully populate isotopes on the dripline, but this reaction has not previously been used at the Cyclotron Institute. In this experiment, a ${}^{58}$Ni beam at 36MeV/u was impinged on Nickel and Beryllium targets to determine which isotopes could be produced. The resulting fragments were measured with two Silicon detectors in order to determine energy loss and production rates for each isotope. The effects of the different targets and the presence of a Carbon stripper foil on production rates will be presented and compared with simulations from the LISE++ program.   

Non-Destructive Analysis of Natural Uranium Pellet

As part of ongoing nuclear forensics research, samples of $^{\mathrm{nat}}$UO$_{\mathrm{2}}$ have been irradiated in a thermal neutron spectrum at the University of Missouri Research Reactor (MURR) with the goal of simulating a pressurized heavy water reactor. Non-destructive gamma ray analysis has been performed on the samples to assay various nuclides in order to determine the burnup and time since irradiation. The quantity of $^{\mathrm{137}}$Cs was used to determine the burnup directly, and a maximum likelihood method has been used to estimate both the burnup and the time since irradiation. This poster will discuss the most recent results of these analyses.   

Precise Measurement of $\alpha_{\mathrm{K}}$ for the 39.76-keV E3 transition in 103Rh: Further Test of Internal Conversion Theory

We have extended our series of precision measurements of internal conversion coefficients (ICC) to include the 39.76-keV, \textit{E3} transition in $^{\mathrm{103}}$Rh. Our goal has been to test the Dirac-Fock ICC calculations, specifically with respect to the role of the atomic vacancy created in the conversion process. We prepared a sample from pure (natural) ruthenium chloride by converting the sample to ruthenium oxide, electrochemically depositing it on an aluminum backing, and subsequently activating it with thermal neutrons at the Texas A{\&}M TRIGA reactor for 20 hours. Decay spectra were then recorded for roughly 120 hours with a HPGe detector that has been precisely efficiency calibrated (\textpm .15{\%} relative precision). In the acquired spectra, all impurities were identified and corrected for accordingly. A program was written using the ROOT framework developed by CERN to extract the area of the 39.76-keV gamma-ray peak from $^{\mathrm{103}}$Rh, which partially overlapped the K$_{\mathrm{\alpha \thinspace }}$x-ray peaks$_{\mathrm{\thinspace }}$from a $^{\mathrm{153}}$Gd impurity. From the ratio of the 39.76-keV peak to the Ruthenium K x rays, we determined a preliminary value for the ICC: $\alpha _{\mathrm{k}}$(39.76)$=$134.6(19). This result agrees well with the theoretical calculation including the atomic vacancy, 135.2, and disagrees with the calculation excluding the vacancy, 127.4. This is consistent with our previous measurements, indicating that the atomic vacancy must be taken into account.   

Event-by-Event Simulations of Early Gluon Fields in High Energy Nuclear Collisions

Collisions of heavy ions are carried out at ultra relativistic speeds at the Relativistic Heavy Ion Collider and the Large Hadron Collider to create Quark Gluon Plasma. The earliest stages of such collisions are dominated by the dynamics of classical gluon fields. The McLerran-Venugopalan (MV) model of color glass condensate provides a model for this process. Previous research has provided an analytic solution for event averaged observables in the MV model. Using the High Performance Research Computing Center (HPRC) at Texas A\&M, we have developed a C++ code to explicitly calculate the initial gluon fields and energy momentum tensor event by event using the analytic recursive solution. The code has been tested against previously known analytic results up to fourth order. We have also have been able to test the convergence of the recursive solution at high orders in time and studied the time evolution of color glass condensate.   

Utilizing Machine Learning for Analysis of Tiara for Texas

The Tiara for Texas detector at Texas A{\&}M University consists of a target chamber housing an array of silicon detectors and surrounded by four high purity germanium clovers that generate voltage pulses proportional to detected gamma ray energies. While some radiation is fully absorbed in one photopeak, others undergo Compton scattering between detectors. This process is thoroughly simulated in GEANT4. Machine learning with scikit-learn allows for the reconstruction of scattered photons to the original energy of the incident gamma ray. In a given simulation, a defined number of rays are emitted from the source. Each ray is marked as an event and its path is tracked. Scikit-learn uses the events' paths to train an algorithm, which recognizes which events should be summed to reconstruct the full gamma ray energy and additional events to test the algorithm. These predictions are not exact, but were analyzed to further understand any discrepancies and increase the effectiveness of the simulation. The results from this research project compare various machine learning techniques to determine which methods should be expanded on in the future.   

Proton Induced X-Ray Emission (PIXE): Determining the Concentration of Samples

We used Proton Induced X-ray Emission (PIXE) as an analysis technique to determine the composition of samples, in particular, the elemental constituents and the concentrations. Each of the samples are bombarded with protons, which in result displaces a lower level electron and causes a higher level electron to fall into its place. This displacement produces characteristic x-rays that are “fingerprints” for each element. The protons supplied for the bombardment are produced and accelerated by the K150 proton beam in the Cyclotron Institute at Texas A&M University. The products are detected by three x-ray detectors: XR-100CR Si-PIN, XR-100SDD, and XR-100T CdTe. The peaks of the spectrum are analyzed using a software analysis tool, GUPIXWIN, to determine the concentration of the known elements of each particular sample. The goals of this work are to test run the Proton Induced X-Ray Emission experimental set up at Texas A&M University (TAMU) and to determine the concentration of thin films containing KBr given by the TAMU Chemical Engineering Department.   

Background Effects on Jet Detection in Heavy Ion Collisions

Heavy ion collisions performed at the LHC and RHIC at large energy scales produce a liquid of quarks and gluons known as a Quark-Gluon Plasma (QGP).~Jets, which are collimated bunches of particles emitted from highly energetic partons, are produced at the early stages of these collisions, and can provide information about the properties of the QGP. Partonic energy loss in the medium can by quantified by measurements of fragmentation functions. However, the high background energies resulting from emissions uncorrelated to the initial hard scatterings in the heavy ion collisions place limitations on jet detection methods and fragmentation measurements. For the purpose of investigating the limitations on these current jet detection methods we generated a heavy ion background based on charged hadron data.~We explore the behavior of a jet finding algorithm with our generated background to examine how the presence of a heavy ion background may affect the measurements of jet properties.   

GPU-accelerated calculations of hadron spectra from heavy-ion collisions

To calculate observables for heavy ion collisions, many events with fluctuating initial conditions are simulated and statistically analyzed. A larger set of simulated collision events yields better statistical results, so decreasing the computation time per event is important. A modern GPU possesses thousands of cores and can efficiently perform identical tasks in parallel. We take advantage of this for performing the Cooper-Frye integrals for the hadron spectra obtained from the numerical output from dissipative hydrodynamic simulations. For a given event, this computation consists of two parts: (1) generating thermal spectra of all hadron resonances as Cooper-Frye integrals over the freeze-out surface, and (2) computing the spectra of stable hadrons by letting unstable resonances decay. We here show results using input from (2$+$1)-dimensional boost-invariant hydrodynamic simulations where both of these steps were accelerated by parallelizing them on a GPU. The GPU implementation yields a speed-up by about two and one orders of magnitude, respectively, for the first and second of these steps. For semi-central Pb$+$Pb collision at the LHC, the time needed for the first step is reduced from 31 minutes on a single CPU to 16 seconds on the GPU, and for the second step from 4 minutes to 20 seconds.   

GEANT Simulation of the ATLAS Zero Degree Calorimeter

The University of Illinois at Urbana-Champaign (UIUC) in collaboration with the ATLAS group at CERN is developing an improved Zero Degree Calorimeter (ZDC) to replace the current ZDC in the ATLAS experiment. The prototype ZDC is a four module detector each made up of 11 alternating layers of tungsten and a liquid active region filled with quantum dots as wavelength shifter and mineral oil solution. When neutrons from the beam collide with the ZDC, the charged hadrons that result from the particle showers produce Cherenkov radiation. This Cherenkov radiation is absorbed and reemitted in a longer wavelength. The re-emitted light is then re-absorbed by second stage wavelength shifters inside hollow quartz rods. The radiation reemitted in the quartz rods is read out through silicon photomultipliers. As a part of ongoing changes to the LHC, the space available between beam pipes is being reduced from 100 mm to 60 mm. Due to this space restriction's effect on the width of the ZDC, there are concerns about the detector's ability to measure the full transverse profile of the particle showers it is designed to contain. The paper will present the results of computer simulations and analysis that were carried out to study the ZDC performance with reduced detector width.   

Readout and Data Acquisition for a Liquid Radiator Radiation Exposure Test

The ATLAS Zero Degree Calorimeter (ZDC) prototype is a tungsten-sampling, oil/quartz radiating calorimeter placed on each side of the interaction point. The ZDC is used in heavy ion runs for centrality measurements. The UIUC group develops a ZDC that is significantly more radiation hard than the currently employed detector. The current ZDC uses scintillating quartz rods placed directly in the beamline whose optical transmission is known to degrade as a function of radiation dosage. Our prototype uses organic wavelength shifters (WLS) dissolved in oil in two stages to take Cherenkov light produced in the oil by the particle shower and guide it to a photodetector. This design allows the quartz rods be located away from the beam center to experience a lower radiation dose, and the oil containing WLS can be replaced periodically to negate radiation damage. Quantum dots are studied as a more radiation hard alternative to WLS. This increase in radiation hardness will allow ATLAS to operate the ZDC after the luminosity upgrades planned for the LHC. A test setup has been developed for the study of radiation hardness of liquid Cherenkov radiators and wavelength shifters. The setup will be described in this presentation with a focus on the readout electronics and data acquisition.   

Two-Stage Cerenkov Radiation Shifting Liquid Zero Degree Calorimeter for \textit{pp}-Run at ATLAS

The Liquid Zero Degree Calorimeter (LqZDC) is an electromagnetic sampling calorimeter that transmits Cerenkov radiation produced by incoming scattered particles using a two-stage wavelength shifting process. The first iteration of the LqZDC was irradiated by a Pb-nuclei beam at the SPS to test the validity of a liquid two-stage shifting process. The first stage transmitted Cerenkov radiation transversely (horizontal) in the active region which consisted of an organic wavelength shifter (WLS), Alexa Fluor 430, dissolved in LAB oil. The second stage transmitted the shifted Cerenkov light transversely (vertical) within a quartz capillary immersed at opposite ends of the active region which consisted of the WLS POPOP dissolved in DMSO. The signal produced by the two-stage process transmits through an incident PMMA fiber to a silicon photomultiplier-equipped pre-amplifier and processed using DRS4/RCDAQ software. However, for the LqZDC to withstand the high radiation environment (1.8 Grad) environment at ATLAS, quantum dots (QD) will replace the organic WLS. The degradative effects and byproducts of QD under large neutron flux (10$^{\mathrm{14}}$ n/cm$^{\mathrm{2}})$ are undescribed in literature, thus are the current focus of this research.   

Evaluating the Radiation Damage to Quartz Rods in the ATLAS Zero Degree Calorimeter

At the Large Hadron Collider, the ATLAS experiment studies particle collisions to explore the fundamental particles of nature. A key instrumentation technology used by the ATLAS experiment are calorimeters for particle energy measurements. UIUC is developing a new Zero-Degree Calorimeter; a hadronic calorimeter located at zero-degrees from the collision axis. It consists of alternating layers of tungsten and oil; passive and active layers, respectively. The passive layers cause intense showers of secondary particles. These particles then produce Cherenkov radiation in the active layer. The oil in the active layer is replaced at a constant rate allowing for very high radiation doses in the detector without deteriorating the radiator material. The active layer includes wavelength shifters that absorb and re-emit isotropically the Cherenkov radiation. In this way, some of the photons arrive at two, hollow quartz rods which are filled by a second stage wavelength shifter. Here the light is absorbed and re-directed to a Silicon Photomultiplier for detection. In this paper, the impact of ionizing radiation on quartz rods will be discussed and the results from attenuation measurements will be presented.   

Multiplicity-Momentum Correlations in Relativistic Nuclear Collisions

The observation of anisotropic collective flow in the small systems produced by proton-proton and proton-nucleus collisions at RHIC and LHC has lead theorists to the radical hypothesis that hydrodynamics can occur without thermal equilibration. We seek measures of equilibration that are independent of anisotropic flow [1]. In this poster we study the effect of thermalization on correlations of multiplicity and transverse-momentum p$_{\mathrm{t}}$. Well known minijet effects in the initial state simultaneously increase multiplicity and p$_{\mathrm{t}}$. leading to a positive correlations between these quantities. We construct a covariance observable that vanishes once the medium created in these collisions reaches thermal equilibrium [2]. We use simulated events from the UrQMD event generator to calculate the value of multiplicity-momentum correlations in Au-Au collisions with a center of mass collision energy of 200 GeV per nucleon. We find a positive value that decreases with increasing centrality, as expected by a partial thermalization calculation [2]. [1] S. Gavin, G. Moschelli, C. Zin, Phys. Rev. C 95, (2017) 064901 [2] S. Gavin, G. Moschelli, C. Zin, in preparation   

3 Body Nuclear Kinematic Modeling

When observing the reactions induced by a $^{10}$Be beam incident on a helium gas target using the Prototype Active-Target Time-Projection Chamber (PAT-TPC), three-body decays were observed, consisting of two $\alpha$ particles and a $^{6}$He nucleus. This three-body decay provides insight into $\alpha$ clustering of light atomic nuclei and increases understanding of astrophysical nuclear synthesis. The experiment consisted of a $\sim38$MeV $^{10}$Be beam targeted on the PAT-TPC containing a 90:10 He:CO$_2$ gas, backed by a Micromegas gaseous amplifier. Detector efficiency will be normalized via a Monte Carlo simulation. Such a simulation requires a robust code base including kinematic modelling of the the 3-body reaction which computes all allowable decay tracks given user-defined input settings. Analysis is ongoing and preliminary results will be presented.   

Visualizing Time Projection Chamber Data for Education and Outreach

The widespread availability of portable computers in the form of smartphones provides a unique opportunity to introduce scientific concepts to a broad audience, for the purpose of education, or for the purpose of sharing exciting developments and research. Unity [1], a free game development platform, has been used to develop a program to visualize 3-D events from a Time Projection Chamber (TPC). The program can be presented as a Virtual Reality (VR) application on a smartphone, which can serve as a standalone demonstration for interested individuals, or as a resource for educators. An interactive experience to watch nuclear events unfold demonstrates the principles of particle detection with a TPC, as well as providing information about the particles present. Different kinds of reactions can be showcased. The current state of tools within this program for outreach and educational purposes will be highlighted and presented in this poster, along with key design concerns and optimizations necessary for running an interactive VR app. The events highlighted in this program are from the S$\pi$RIT TPC [2], but the program can be applied to other 3-D detectors. [1] "Unity - Game Engine": https://unity3d.com/ accessed 7/25/2017 [2] R. Shane et al.: Nucl. Instr. Meth. A 784, 513 (2015).   

Development of a 3-D Nuclear Event Visualization Program Using Unity

Simulations have become increasingly important for science and there is an increasing emphasis on the visualization of simulations within a Virtual Reality (VR) environment. Our group is exploring this capability as a visualization tool not just for those curious about science, but also for educational purposes for K-12 students. Using data collected in 3-D by a Time Projection Chamber (TPC), we are able to visualize nuclear and cosmic events. The Unity game engine [1] was used to recreate the TPC to visualize these events and construct a VR application. The methods used to create these simulations will be presented along with an example of a simulation. I will also present on the development and testing of this program, which I carried out this past summer at MSU as part of an REU program. We used data from the S$\pi$RIT TPC [2], but the software can be applied to other 3-D detectors. This work is supported by the U.S. Department of Energy under Grant Nos. DE-SC0014530, DE-NA0002923 and US NSF under Grant No. PHY-1565546. Sources: [1] "Unity - Game Engine": https://unity3d.com/ accessed 7/25/2017 [2] R. Shane et al.: Nucl. Instr. Meth. A 784, 513 (2015).   

Computing Solutions of the Schrodinger Equation for Coupled Channels Nuclear Scattering Problems with Non-Local Potentials using the R-Matrix Method

The calculable R-matrix method has been shown to be an efficient method for describing scattering states from nuclear interactions. The method has been applied with success to calculate solutions to the Schrodinger equation in two body, single channel scattering reactions. The purpose of this study is to extend the R-matrix method to calculate solutions to a non-local, coupled channels reaction. Such a method will calculate wavefunctions using the local and non-local interactions within each channel, and also include coupling potentials between the channels. We use the Woods-Saxon and Perey Buck potential models for the local and non-local potentials. Calculating solutions for a coupled channels scattering problem is approached by using the R-matrix method with a Lagrange mesh. While this study focused on a two coupled channels case, the method could be applied to more channels, at the cost of more computation time with each additional channel.   

Increasing The Electric Field For An Improved Search For Time-Reversal Violation Using Radium-225

Radium-225 atoms, because of their unusual pear-shaped nuclei, have an enhanced sensitivity to the violation of time reversal symmetry. A breakdown of this fundamental symmetry could help explain the apparent scarcity of antimatter in the Universe. Our goal is to improve the statistical sensitivity of an ongoing experiment that precisely measures the EDM of Radium-225. This can be done by increasing the electric field acting on the Radium atoms. We do this by increasing the voltage that can be reliably applied between two electrodes, and narrowing the gap between them. We use a varying high voltage system to condition the electrodes using incremental voltage ramp tests to achieve higher voltage potential differences. Using an adjustable gap mount to change the distance between the electrodes, specific metals for their composition, and a clean room procedure to keep particulates out of the system, we produce a higher and more stable electric field. Progress is marked by measurements of the leakage current between the electrodes during our incremental voltage ramp tests or emulated tests of the actual experiment, with low and constant current showing stability of the field.   

Exploring Bayesian model selection methods for effective field theory expansions

A fundamental understanding of the microscopic properties and interactions of nuclei has long evaded physicists due to the complex nature of quantum chromodynamics (QCD). One approach to modeling nuclear interactions is known as chiral effective field theory (EFT). Today, the method’s greatest limitation lies in the approximation of interaction potentials and their corresponding uncertainties. Computing EFT expansion coefficients, known as Low-Energy Constants (LECs), from experimental data reduces to a problem of statistics and fitting. In the conventional approach, the fitting is done using frequentist methods that fail to evaluate the quality of the model itself (e.g., how many orders to use) in addition to its fit to the data. By utilizing Bayesian statistical methods for model selection, the model’s quality can be taken into account, providing a more controlled and robust EFT expansion. My research involves probing different Bayesian model checking techniques to determine the most effective means for use with estimating the values of LECs. In particular, we are using model problems to explore the Bayesian calculation of an EFT expansion’s evidence and an approximation to this value known as the WAIC (Widely Applicable Information Criterion).   

Chiral Phase Structure in 2+1 Flavor Soft-Wall AdS/QCD

In this work we analyze the structure of the chiral phase transition in a soft-wall model of AdS/QCD. In our previous work we explored a 2-flavor-symmetric model which yielded a second-order transition for massless quarks and crossover transitions for massive quarks. We have extended the model to 2+1 flavors to see the effects of different quark masses on the order of the chiral transition. Using a holographic approach, we investigate the Columbia Plot produced by lattice gauge theory. We obtain independent sources of explicit and spontaneous symmetry breaking, and through black hole thermodynamics explore the effects of high temperature and chemical potential on the chiral condensate. We investigate various values of the light and strange quark masses and find the critical line separating first-order from crossover transitions in the mass plane. In the case of equal quark masses, a mass of 35 MeV separates first-order from crossover transitions. At the physical point we find that the transition is first-order. Our work supplements lattice simulations and other holographic studies that do not sufficiently treat finite baryon density. However, we find that the phase structure is qualitatively independent of chemical potential. Thus, a tri-critical point is absent from our model.   

Implementing the correlated fermi gas nuclear model for quasielastic neutrino-nucleus scattering

When studying neutrino oscillations an understanding of charged current quasielastic (CCQE) neutrino-nucleus scattering is imperative. This interaction depends on a nuclear model as well as knowledge of form factors. Neutrino experiments, such as MiniBooNE [1], often use the Relativistic Fermi Gas (RFG) nuclear model [2]. Recently, the Correlated Fermi Gas (CFG) nuclear model was suggested in [3], based on inclusive and exclusive scattering experiments at JLab. We implement the CFG model for CCQE scattering. In particular, we provide analytic expressions for this implementation that can be used to analyze current and future neutrino CCQE data. References: [1] A. A. Aguilar-Arevalo et al. [MiniBooNE Collaboration], PR D 81, 092005 (2010). [2] R. A. Smith and E. J. Moniz, Nucl. Phys. B 43, 605 (1972). [3] O. Hen, B. A. Li, W. J. Guo, L. B. Weinstein and E. Piasetzky, PR C 91, 025803 (2015).   

Separating form factor and nuclear model effects in quasielastic neutrino-nucleus scattering

When studying neutrino oscillations an understanding of charged current quasielastic (CCQE) neutrino-nucleus scattering is imperative. This interaction depends on a nuclear model as well as knowledge of form factors. In the past, CCQE data from the MiniBooNE experiment was analyzed assuming the Relativistic Fermi Gas (RFG) nuclear model [1], an axial dipole form factor in [2], and using the the z-expansion for the axial form factor in [3]. We present the first analysis that combines a non-RFG nuclear model, in particular the Correlated Fermi Gas nuclear model (CFG) of [4], and the z expansion for the axial form factor. This will allow us to separate form factor and nuclear model effects in CCQE scattering. References: [1] R. A. Smith and E. J. Moniz, Nucl. Phys. B 43, 605 (1972). [2] A. A. Aguilar-Arevalo et al. [MiniBooNE Collaboration], PR D 81, 092005 (2010). [3] B. Bhattacharya, R. J. Hill, G. Paz. PR D 84, 073006 (2011). [4] O. Hen, B. A. Li, W. J. Guo, L. B. Weinstein and E. Piasetzky, PR C 91, 025803 (2015).   

Characterization of High Purity Germanium Detector efficiency using GEANT4

We report on the performance of a high-purity germanium detector recently deployed at the second level of the Kimballton Underground Research Facility for low background counting. In particular we will describe a GEANT4-based simulation developed to estimate the efficiency of the detector for user-configurable sample geometries and gamma-ray energies. The sensitivity to common isotopes of interest including 238U, 232Th and 40K will be presented. This facility will benefit materials screening efforts to select components for use in future rare event experiments such as those searching for neutrinoless double-beta decay and dark matter.   

Optimization of scintillator loading with the tellurium-130 isotope for long-term stability

Tellurium-130 was selected as the isotope for the SNO$+$ neutrinoless double beta decay search, as $^{\mathrm{130}}$Te decays to $^{\mathrm{130}}$Xe via double beta decay. Linear alkyl benzene(LAB) is the liquid scintillator for the SNO$+$ experiment. To load tellurium into scintillator, it is combined with 1,2-butanediol to form an organometallic complex, commonly called tellurium butanediol (TeBD). This study focuses on maximizing the percentage of tellurium loaded into scintillator and evaluates the complex's long-term stability. Studies on the effect of nucleation due to imperfections in the detector's surface and external particulates were employed by filtration and induced nucleation. The impact of water on the stability of TeBD complex was evaluated by liquid-nitrogen sparging, variability in pH and induced humidity. Alternative loading methods were evaluated, including the addition of stability-inducing organic compounds. Samples of tellurium-loaded scintillator were synthesized, treated, and consistently monitored in a controlled environment. It was found that the hydronium ions cause precipitation in the loaded scintillator, demonstrating that water has a detrimental effect on long-term stability. Optimization of loaded scintillator stability can contribute to the SNO$+$ double beta decay search.   

Characterizing Background Events in Neutron Transmutation Doped Thermistors for CUORE-0

The Cryogenic Underground Observatory for Rare Events (CUORE) is a ton-scale neutrinoless double-beta decay experiment operating at the Laboratori Nazionali del Gran Sasso (LNGS). The experiment is comprised of 988 TeO$_2$ bolometric crystals arranged into 19 towers and operated at a temperature of $\sim$15 mK. A neutron-transmutation-doped (NTD) Ge thermistor measures the thermal response from particles incident on the crystals. However, bulk and surface contamination of the NTD thermistors themselves produce distorted thermal responses inside the thermistor volume. Although these pulses are efficiently removed from the double-beta decay analysis by pulse shape cuts, they can be used to extract information about thermistor contamination. I will present a multifaceted approach to characterize these events, in which I implement an improved hot-electron thermal model, Geant4 Monte Carlo simulations of background events, and data from a previous experiment, CUORE-0, reprocessed with a new optimal filter. Using this approach, rates and energy deposition from contamination inside the NTD thermistors are measured, giving us better understanding of a CUORE background source.   

Electrostatic simulation of a liquid xenon purity monitor

Liquid xenon detectors like the proposed nEXO neutrinoless double beta decay experiment use scintillation and ionization signals to track the position and energy of radiation events in the detector. Ionization signals can be diminished by impurities in the xenon. We have designed a liquid xenon purity monitor with high voltage switching capability to measure long electron lifetimes for studying detector materials. We discuss the use of COMSOL electrostatic simulation software to model the field cage of this purity monitor and simulate the electron transport efficiency. An intensive study of the high voltage switching region and shielding grids was completed to ensure uniform electric fields and grid transparencies in the purity monitor.   

Hamiltonian Markov Chain Monte Carlo Methods for the CUORE Neutrinoless Double Beta Decay Sensitivity

The CUORE experiment is a large-scale bolometric detector seeking to observe the never-before-seen process of neutrinoless double beta decay. Predictions for CUORE's sensitivity to neutrinoless double beta decay allow for an understanding of the half-life ranges that the detector can probe, and also to evaluate the relative importance of different detector parameters. Currently, CUORE uses a Bayesian analysis based in BAT, which uses Metropolis-Hastings Markov Chain Monte Carlo, for its sensitivity studies. My work evaluates the viability and potential improvements of switching the Bayesian analysis to Hamiltonian Monte Carlo, realized through the program Stan and its Morpho interface. I demonstrate that the BAT study can be successfully recreated in Stan, and perform a detailed comparison between the results and computation times of the two methods.   

Comparing CUORE Calibration Data to Simulations

The Cryogenic Underground Observatory for Rare Events (CUORE) is a ton-scale experiment located at the Laboratori Nazionali del Gran Sasso searching for the neutrinoless double-beta $(0\nu\beta\beta)$ decay of ${}^{130}$Te. Operating at $\sim$15 mK, CUORE is arranged into 19 towers with 988 TeO$_2$ crystals in total that serve as both the sources and detectors of the ${}^{130}$Te decay. The energy response of each individual crystal is calibrated at various energies using ${}^{232}$Th source strings placed within the array of detectors. Analyzing the differences between calibration and simulated calibration data provides valuable information on the performance of our Monte Carlo simulations, which are important for understanding our physics energy spectrum and background sources. In this poster, I will discuss a comparison of recent CUORE calibration data to Monte Carlo simulations of the data for the strongest lines in the $^{232}$Th decay chain that are used to calibrate the experiment.   

Modeling Neutral-Current Neutrino Interactions in Liquid Argon

Studies of supernova neutrinos provide knowledge of neutrino oscillations and supernova physics. The Deep Underground Neutrino Experiment (DUNE) will enable exploration of the three-flavor model of neutrino physics and solve questions in regards to the dynamics of supernova, the stability of matter, and matter-antimatter asymmetry. DUNE will use a Liquid Argon Time-Projection Chamber (LArTPC) which will be able to detect charged-current, neutral-current, and elastic-scattering interactions. The neutral current $\nu-^{40}{Ar}$ interaction leaves an excited $^{40}Ar$ nucleus that releases a 9.8 MeV gamma which is analyzed for the LArTPC. This project creates a smearing file for SNOwGLoBES, an event rate calculator, that corresponds to the DUNE detector simulation for this interaction. The expected number of neutral current supernova neutrino events in liquid $^{40}{Ar}$ is determined and the observable energy distribution is examined.   

Scintillator Detector Characterization for $\beta $-Delayed Neutron Emission

Previous methods to study $\beta $-delayed neutron ($\beta $DN) emission have yielded high efficiency or modest energy resolution, but not both. A new method to study $\beta $DN emission utilizes and ion trap to keep the radioactive ions effectively at rest and a series of detectors to measure the time of flight of the recoil ion and other decay radiation. A procedure and mechanism were developed to systematically characterize the position and low-energy response of the $\Delta $E-E scintillator detectors utilized with the ion trap. The mechanism was designed and subsequently used to hold various sources, including $^{\mathrm{113}}$Sn and $^{\mathrm{207}}$Bi, at a set distance from the face of the $\Delta $E scintillator, and rotate to characterize all areas of the detector.   

Spin Propagation Simulation for the NSR Apparatus

The Neutron Spin Rotation (NSR) Collaboration investigates the hadronic weak interaction and, in a recent experiment, possible spin-dependent fifth forces. One such interaction between a neutron and nearby material acts as a pseudo-magnetic force causing the neutron spin to process, as first investigated experimentally by Piegsa and Pignol[1]. The NSR apparatus functions as a cold-neutron polarimeter that is sensitive enough to measure rotations in the 10-7 rad range. In the 5th-force experiment neutrons pass near a slab of material. Since the effect falls off exponentially and we want to take advantage of the large 10cmx10cm beam at LANSCE, the target has many slabs of different densities with several mm gaps between them through which the neutrons propagate. Due the sensitivity of the apparatus, it is vital to investigate and reduce the effects of stray magnetic fields, as they can cause large rotations as the neutrons pass through the target region. My work has been modifying a neutron transport simulation to include the precession of spins about realistic magnetic fields in the low-field regions of the NSR apparatus. Results will be presented. [1] F. M. Piegsa and G. Pignol Limits on the Axial Coupling Constant of the New Light Bosons Phys. Rev. Lett. 108, 181801 (2012)   

Geant4 simulations of NIST beam neutron lifetime experiment

A free neutron is unstable and its decay is described by the Standard Model as the transformation of a down quark into an up quark through the weak interaction. Precise measurements of the neutron lifetime test the validity of the theory of the weak interaction and provide useful information for the predictions of the theory of Big Bang nucleosynthesis of the primordial helium abundance in the universe and the number of different types of light neutrinos $N_{\nu}$. The predominant experimental methods for determination of the neutron lifetime are commonly called “beam” and “bottle” methods, and the most recent uses of each method do not agree with each other within their stated uncertainties. An improved experiment of the beam technique, which uses magnetic and electric fields to trap and guide the decay protons of a beam of cold neutrons to a detector, is in progress at the National Institute of Standards and Technology, Gaithersburg, MD with a precision goal of 0.1%. This study uses both the Geant4 simulation toolkit and the ROOT analysis framework to examine the effects of certain experimental conditions on the precision, in order to understand and reduce systematic uncertainties, especially those related to proton backscattering from the detector.   

Neutron Production from Atmospheric Neutrino Interactions at the Sudbury Neutrino Observatory

In this analysis we measure the neutron production from atmospheric neutrino interactions in heavy water (D2O) at the Sudbury Neutrino Observatory (SNO). These neutrons form a significant background to nucleon decay analyses but production rates are not very well known mainly due to uncertainties on neutrino cross-section models and final state interactions (FSI). This analysis opens up the possibility to distinguish neutrino and antineutrino events in order to measure more precisely the neutrino mass hierarchy through neutron tagging. We use a likelihood-based reconstruction algorithm to identify the characteristics of the Cherenkov radiation cone from final state particles yielded by atmospheric neutrino interactions and measure its energy and position, and identify the number of particles and neutrino flavor. In this poster we detail the algorithm, how we calibrate energy scale and we show preliminary measurement of the neutron multiplicity as a function of the charged lepton energy, comparing it to the GENIE model.   

Studies of Instrumental Backgrounds in the MAJORANA DEMONSTRATOR

The MJD at the Sanford Underground Research Facilities employs an array of germanium detectors to search for neutrinoless double-beta decay of $^{76}$Ge. An analysis framework is currently used to process recorded event-pulses and to remove instrumental background pulses with high efficiency. However, this rejection relies on identifying all different types of non-physical pulses. The aim was to find the general properties that define good physical events in the detectors. This could provide an independent early-stage detection system for potential new types of non-physical events caused, for example, by changes in the electronics and data acquisition systems. To achieve this, we treated the digitized raw waveforms of events as statistical distributions, and studied the (normalized) moments such as mean, RMS, skewness and kurtosis. Correlations between these parameters indicate a clear separation for some types of non-physical pulses with respect to the continuous distribution of good physical events population. Here we present results of a study using this method on MJD data, and a comparison with the existing data techniques. The underlying method promises to be applicable on a wider basis, allowing to pre-filter non-physical events recorded with Ge-detectors in general.   

Ultra-low Background Ge Counter Abstract

The purpose of this project is to design a new ultra-low radioactive background germanium (Ge) counter using the MAJORANA low-mass front-end (LMFE), the lowest background Ge front-end readout electronics in the world. Sensitive Ge counters for radioactivity assays are important for the design and construction of next generation underground experiments. We are building a prototype cryostat for testing the hardware compatibility and electronics performance of the LMFE that will be modified for this assay spectrometer. This poster will discuss the general design of the prototype cryostat, specifically my contributions in designing the mounting hardware for the Ge crystal and involvement with the setup of the testing system.   

Development of Data Quality and Analysis Tools for the MAJORANA DEMONSTRATOR

The MAJORANA DEMONSTRATOR is a high-purity germanium-76 (HPGe) detector array consisting of p-type point contact detectors operating 4850 ft below ground in the Sanford Underground Research Facility in South Dakota. The DEMONSTRATOR is designed to search for neutrinoless double-beta decay while determining the feasibility of the construction of a future tonne-scale modular detector. The purpose of this work was to develop data analysis tools for data validation and time coincidences, and to make a search for alpha-decay background related coincidences. First, a program was developed to track changes in the bias voltage applied to individual HPGe detectors. This tool allows the identification of any runs where the bias on detectors has changed, flagging partially biased detectors to be excluded from the physics analyses. Next, an analysis tool was developed to search for possible delayed coincidences associated with the$\thinspace $beta-alpha and alpha-alpha radioactive decays in the U-238 and Th-232 chains. The initial analysis using this tool did not find any candidates, indicating very low alpha related backgrounds.   

Depolarization per bounce of ultracold neutrons in collision with material guides within varying ambient magnetic holding fields

Material depolarization of “ultracold” neutrons (UCN), neutrons with energies of $\sim$100neV, is studied to understand and control systematic effects in experiments where polarized UCN interact with materials, such as polarized beta-decay experiments. A number of “PPM Depol” experiments have been performed by the Los Alamos National Lab UCN team to test the probability of depolarization per bounce of UCN within material test guides. In one of these experiments, different guides were mounted within a varying ambient longitudinal holding field adjustable from 10G to 260G, which allowed the measurement to be repeated with different holding field strengths. Following analysis of the data from this experiment, Monte Carlo simulations were used to investigate systematic effects associated with poorly-constrained properties of the experiment, such as guide specularity and guide loss per bounce, and the UCN energy spectrum. The method of analysis as well as extracted depolarization probabilities per bounce for copper guides of various surface preparations and stainless steel guides, all as a function of holding field strength, will be presented. Comparisons between simulations and data will also be used to discuss systematic effects present in the analysis.   

The Structure of 34Mg Nuclei

In the chart of nuclei below the beta-stability line, there are regions called islands of inversion where nuclei are expected have a spherical ground state, but it has been determined that these nuclei have a deformed ground state. This project was part of an ongoing investigation with the goal of obtaining new information about 34Mg and 34Al, which lie near an island of inversion. A beam of 34Mg was sent to the center of an array of plastic scintillators and HPGe detectors to collect data from the isotope's beta decay. This isotope beta decays to 34Al and to 34Si. The analysis softwares ROOT and GRSISort were used to sort the data into analysis trees, from which certain histograms were extracted. These histograms were used to determine an initial list of gamma ray transitions associated with the relatively fast decays of 34Mg and 34Al. Since the efficiencies of gamma ray detection are known, the true number of counts from each transition can be determined. This was done to order the gamma ray transitions into a nuclear level scheme. Future work on this subject will include the analysis of the angular correlations of the transitions found to determine spins of states populated in the 34Al and Si daughter nuclei as well as shedding light on the isomer in 34Al.   

The Cross Section of Xenon-134

In neutrinoless double beta decay experiments, Xenon-136 is an isotope often used. These sources, however, contain significant amounts of Xenon-134, an isotope that has no recorded cross-section. Additionally, the de-excitation of a particular nuclear state of Xenon-134 almost mimics the estimated Q-value of the neutrinoless double beta decay of Xenon-136. So, to improve the clarity of 0$\nu \beta \beta $ experiments this project focuses on creating a cross-section for Xenon-134. This was achieved by activating a source of Xenon-134 in gas cells at Triangle Universities National Laboratory (TUNL) and using clover detectors to analyze the decay. This will allow for an in depth look at the background of Xenon-134 which will provide insight into all 0$\nu \beta \beta $ experiments that contain Xenon-136.   

Preliminary Analysis of Magnetic Field Data from the UCN$\tau$ Experiment

The free neutron lifetime $\tau_n$ is a physical constant that is associated with a variety of experimental tests for new physics. For example, if $\tau_n$ is known to within 0.01\% (an error of about $\pm$0.1 s) it can be combined with other $\beta$-decay observables to test the Standard Model. The UCN$\tau$ experiment has the ultimate goal of measuring the free neutron lifetime with this precision. The experiment uses a trap composed of a bowl-shaped Halbach array of permanent magnets inside of a vacuum jacket surrounded by field coils to contain polarized, ultracold neutrons (UCN), which are allowed to decay inside the trap. The magnetic array, in conjunction with gravity, keeps the UCN from escaping while the field coils prevent the UCN from depolarizing. However, there will be a systematic error if UCN leave the trap for a reason other than decay. This could occur if UCN become depolarized by interacting with magnetic field zeroes or if some surface region of the array has a magnetic field insufficient to repel trapped UCN. To check for this, a magnetic mapper was deployed to make a preliminary examination of the field in the UCN$\tau$ trap. We will describe the repeatability and precision of the magnetic mapper and present analysis of the magnetic field maps recorded.   

Comparing Simulated and Experimental Data from UCN$\tau$

The UCN$\tau$ experiment is designed to measure the average lifetime of a free neutron ($\tau{}_{n}$) by trapping ultracold neutrons (UCN) in a magneto-gravitational trap and allowing them to $\beta$-decay, with the ultimate goal of minimizing the uncertainty to approximately 0.01\% (0.1 s). Understanding the systematics of the experiment at the level necessary to reach this high precision may help to better understand the disparity between measurements from cold neutron beam and UCN bottle experiments ($\tau{}_{n}\sim$888 s and $\tau{}_{n}\sim$878 s, respectively). To assist in evaluating systemics that might conceivably contribute at this level, a neutron spin-tracking Monte Carlo simulation, which models a UCN population's behavior throughout a run, is currently under development. The simulation will utilize an empirical map of the magnetic field in the trap (see poster by K. Hoffman) by interpolating the field between measured points (see poster by J. Felkins) in order to model the depolarization mechanism with high fidelity. As a preliminary step, I have checked that the Monte Carlo model can reasonably reproduce the observed behavior of the experiment. In particular, I will present a comparison between simulated data and data acquired from the 2016-2017 UCN$\tau$ run cycle.   

Transport of ions using RF Carpets in Helium Gas

Radio-Frequency (RF) carpet are critical components of large volume gas cells used to thermalize radioactive ion beams produced at in-flight facilities. RF carpets are formed by a series of co-centric conductive rings on which an alternating potential (in the radio-frequency range) is applied with opposite polarity on adjacent rings. This results in a strong repelling force that keep the ions a certain distance from the carpet. The transport of ions using RF carpet is accomplished using either a potential gradient applied on the individual all strips or traveling wave (using the so-called “ion surfing method”). A test setup has been constructed at the University of Notre Dame to perform studies on the repelling of ions using RF carpets. This test setup has recently been improved by the addiction of circuitry elements allowing the transport of ions using the ion surfing method. The developed circuitry, together with transport results for various ion beam currents, electric force applied on the ions, and traveling wave amplitude and speed will be presented   

Testing HECTOR's Efficiency Post-Collimator Addition

To better refine models of stellar nucleosynthesis, various characteristics of nuclides must be well studied This information is crucial for models to correctly predict observed abundances. Here, proton capture reaction cross sections for $^{\mathrm{102}}$Pd, $^{\mathrm{108}}$Cd, and $^{\mathrm{110}}$Cd, important for the astrophysical p-process, were studied using Notre Dame's FN 10MV. The High EffiCiency TOtal absorption spectrometeR (HECTOR) was used to measure the gamma ray spectra of each source for different beam energies. Part way through the experiment, a collimator was added to HECTOR to provide a better beam tune. As this affects the efficiency of HECTOR by an unknown amount, it must be quantified before much of the desired target data is to be analyzed for cross sections. This was done by examining $^{\mathrm{27}}$Al resonance and $^{\mathrm{60}}$Co calibration runs with and without the collimator and comparing the calculated efficiency with Geant4 simulations of HECTOR with the same collimator configuration. The results of the data analysis will be compared with the Geant4 simulation which provides a strong agreement with the data.   

Particle-Induced Gamma-ray Emission Spectroscopy Over a Broad Range of Elements

Ion beam analysis is a common application of nuclear physics that allows elemental and isotopic information about materials to be determined from accelerated light ion beams~ One of the best~know~ion beam analysis techniques is Particle-Induced Gamma-ray Emission (PIGE) spectroscopy,~which can be used \textit{ex vacuo} to identify the elements of interest in almost any solid target. The energies of the gamma-rays emitted by excited nuclei will be unique to each element and depend on its nuclear structure.~ For the most sensitivity, the accelerated ions should exceed the Coulomb barrier of the target, but many isotopes are known to be accessible to PIGE even below the Coulomb barrier. To explore the sensitivity of PIGE across the periodic table, PIGE measurements were made on elements with Z = 5, 9, 11-15, 17, 19-35, 37, 42, 44-48, 53, 56, 60, 62, 73, and 74 using 3.4 MeV protons. These measurements will be compared with literature values and be used as a basis for comparison with higher-energy proton beams available at the University of Notre Dame's St. Andre accelerator when it comes online this Fall.~ The beam normalization technique of using atmospheric argon and its 1459 keV gamma-ray to better estimate the integrated beam on target will also be discussed.~   

Modification of the Microchannel Plate (MCP) Detectors for the Recoil Mass Separator St. George for the Improvement of Particle Identification in (}$\alpha $\textbf{,}$\gamma $\textbf{) Reaction Experiments

The Recoil Mass Separator St George in Notre Dame's Nuclear Science Laboratory (NSL) is being used for the study of low energy ($\alpha $,$\gamma )$ reactions using inverse kinematics to better understand the helium burning processes in stars. The St. George detector system uses two MCP detectors and a silicon strip detector to measure time of flight and energy, respectively, of ions reaching the end of the device. To improve the time resolution of the MCP detectors and to add position sensitivity, we modified the circuitry of both MCP detectors and added a segmented anode with readout via two delay lines. Details of the modifications and initial results showing the effects on time resolution and the added position information will be presented.   

Calculating Absolute Transition Probabilities for Deformed Nuclei in the Rare-Earth Region

Absolute transition probabilities are the cornerstone of understanding nuclear structure physics in comparison to nuclear models. We have developed a code to calculate absolute transition probabilities from measured lifetimes, using a Python script and a Mathematica notebook. Both of these methods take pertinent quantities such as the lifetime of a given state, the energy and intensity of the emitted gamma ray, and the multipolarities of the transitions to calculate the appropriate B(E1), B(E2), B(M1) or in general, any B($\sigma\lambda$) values. The program allows for the inclusion of mixing ratios of different multipolarities and the electron conversion of gamma-rays to correct for their intensities, and yields results in absolute units or results normalized to Weisskopf units. The code has been tested against available data in a wide range of nuclei from the rare earth region (28 in total), including $^{146-154}$Sm, $^{154-160}$Gd, $^{158-164}$Dy, $^{162-170}$Er, $^{168-176}$Yb, and $^{174-182}$Hf. It will be available from the Notre Dame Nuclear Science Laboratory webpage for use by the community.   

Rotational Analysis of Beryllium Isotopes Using JISP16 and Daejeon16 Interactions

Rotational bands emerge in \textit{ab initio} no core configuration interaction (NCCI) calculations in several beryllium isotopes. This is shown by rotational patterns in excitation energies, electromagnetic moments, and electromagnetic transitions as functions of the angular momentum. In order for NCCI calculations to correctly describe the nucleus, the NCCI calculation must be based on a realistic nucleon-nucleon interaction. The nucleon-nucleon interaction JISP16 has been previously used to calculate the rotational bands in beryllium isotopes. However, a new nucleon-nucleon interaction, Daejeon16, has been shown to provide more accurate ground state energies of light nuclei. The two nucleon-nucleon interactions, JISP16 and Daejeon16, are used to describe rotational bands of the beryllium isotopes $^7$Be, $^8$Be, and $^9$Be. For each isotope and interaction, rotational bands are determined using a range of basis parameters to determine which interaction yields rotational band parameters which most closely match experimental values. Various methods of extrapolation are used to determine converged values of rotational band parameters.   

Calculating Electron Drift Velocity and Development of the ND Cube Detector

Active-target detectors are crucial for reactions with radioactive beams because of their high efficiency and good energy resolution. Their significant amount of target material enhances the ability to perform experiments at lower beam rates. At University of Notre Dame, we are developing an active-target time-projection chamber called the ND Cube that will image charged-particle tracks. To understand properties of the detector such as electron drift velocity and straggling in the detector gas, calculations were obtained for a He-CO2 mixture as a function of electric field and pressure. Higher electric field strengths and lower pressures produced higher drift velocities. Increased pressures minimized both longitudinal and transverse straggling whereas electric field strength had no direct effect on straggling in either direction. Additionally, the field cage of the detector was completed and electrical feedthroughs were designed and constructed. The completion of the field cage included the assembly and testing of its resistor chain. The cage will be tested in experimental conditions and used in future measurements of drift velocity and straggling. Experimental data will be compared with our calculated results and aid our understanding of the detector design.   

PIXE and XRF Analysis of Roman Denarii

A set of Roman Denarii from the republican to the imperial period (140BC-240AD) has been studied using X-ray fluorescent (XRF) scanning and proton induced x-ray emission (PIXE) techniques. XRF and PIXE are commonly used in the study of cultural heritage objects because they are nondestructive. The combination of these two methods is also unique because of the ability to penetrate the sample with a broader spectrum of depths and energies than either could achieve on its own. The coins are from a large span of Roman history and their analysis serves to follow the economic and political change of the era using the relative silver and copper contents in each sample. In addition to analyzing the samples, the study sought to compare these two common analysis techniques and to explore the use of a standard to examine any shortcomings in either of the methods. Data sets were compared and then adjusted to a calibration curve which was created from the analysis of a number of standard solutions. The concentrations of the standard solutions were confirmed using inductively coupled plasma spectroscopy. Through this we were able to assemble results which will progress the basis of understanding of PIXE and XRF techniques as well as increase the wealth of knowledge of Ancient Roman currency.   

Commissioning of a Faraday cup for the Solenoid Spectrometer for Nuclear Astrophysics (SSNAP)

The Solenoid Spectrometer for Nuclear Astrophysics (SSNAP) is a HELIOS-like helical orbit spectrometer being developed at the University of Notre Dame. Designed around position-sensitive silicon detectors set along the axis of the second TwinSol solenoid, it will improve our capacity to study nucleon transfer reactions. The study of nucleon transfer reactions gives us insight into many nucleosynthesis processes occurring in astrophysical events, such as novae bursts, neutron-star collisions, among others. SSNAP will provide quick and accurate measurements to many nuclear properties, such as nuclear cross sections, branching ratios, and nuclear spectroscopy. It will also provide easy particle identification by using Time-of-Flight measurements. A Faraday cup was commissioned as part of recent developments to SSNAP in order to normalize the data. This work focuses on the design requirements, production and testing of the Faraday cup.   

Analysis of Colonial Currency

This project entailed studying the cellulose in paper, the ink, colorants, and other materials used to produce American colonial currency. The technique primarily used in this project was X-Ray Fluorescence Spectroscopy (XRF). XRF mapping was used to provide both elemental analysis of large-scale objects as well as microscopic examination of individual pigment particles in ink, in addition to the inorganic additives used to prepare paper. The combination of elemental mapping with Fourier Transform Infrared (FTIR) and Raman Spectroscopies permits an efficient analysis of the currency. These spectroscopic methods help identify the molecular composition of the pigments. This combination of atomic and molecular analytical techniques provided an in-depth characterization of the paper currency on the macro, micro, and molecular levels. We have identified several of pigments that were used in the preparation of inks and colorants. Also, different inorganic crystals, such as alumina-silicates, have been detected in different papers. The FTIR spectroscopy allowed us to determine the type of cellulose fiber used in the production of paper currency. Our future research will be directed toward revealing important historical relationships between currencies printed throughout the colonies.   

Optimizing MicroMegas Design for Experiments in Nuclear Clustering

An Active Target Time Projection chamber is a detector which uses a gaseous target to simultaneously track charged particles from nuclear reactions and are important for radioactive beam experiments. MicroMegas are an important part of this detector because they give us the position data needed to track these particles. Charged particles create free electrons from ionization of the gas and these electrons are drifted towards the Micromegas, where they are turned into an electronic signal that is read by the front-end electronics. The arrangement of the copper strips on the MicroMegas are key to experiments because it is closely related to the resolution of our measurements. We need to test these prototypes in our ND Cube Active Target Chamber in order to see which design is most effective. Using Altium Designer, I have begun designing a prototype MicroMegas with concentric rings of pads centered around a cluster of hexagonal pads. This design allows us to maximize resolution by maximizing the number of pads for the surface area of the board, and, by using 8 octet pads to create a ring, we increase the amount of pads in each circle. I will present the results of our first design and the outlook for future studies and designs.   

Offline commissioning and simulations of the Notre Dame MR-TOF

Multi-Reflection Time-OF-Flight mass spectrometers (MR-TOF) are more and more commonly used in nuclear physics as either a high-resolution mass separator or even to perform high-precision mass measurements. One such MR-TOF has been constructed at the University of Notre Dame (ND) to be used as isobar separator for the future N $=$ 126 beam factor at Argonne National Laboratory. The first series of off-line commissioning of the ND MR-TOF will be presented. A careful optimization of the potential on the various mirror electrodes and the injection optics have resulted in resolving powers reaching 60,000 after 200 round trips. However, it was also observed that as the time-of-flight increases, the efficiency drops rapidly. Detailed ion optical simulations were then performed revealing the need for a set of steering electrode up stream from the MR-TOF.   

Evidence for Two-Phonon Transverse Wobbling in $^{135}$Pr

Evidence is presented for a second transverse wobbling band in $^{135}$Pr, the first two-phonon wobbling band to be observed outside of the A$\sim$160 region of the nuclear chart. Wobbling, a unique indicator of triaxially-shaped nuclei, is characterized by the $\Delta I$=1, $E2$ nature of interband linking transitions, and transverse wobbling is characterized by a decrease in the wobbling energy as angular momentum increases. Previous work has investigated the one-phonon wobbling band in $^{135}$Pr, but this analysis of high-statistics data using the $^{123}$Sb($^{16}$O@80 MeV,4n)$^{135}$Pr reaction in the Gammasphere array at Argonne National Laboratory reveals that $^{135}$Pr is robust enough to support two vibrational modes of wobbling. This definitively shows that multiple-phonon wobbling is not confined to any one region of the nuclear chart. In addition, this analysis yields more precise measurements of angular distributions and mixing ratios across the level scheme of $^{135}$Pr.   

X-ray Fluorescence Spectroscopy of Pre-Federal American Currency

X-ray Fluorescence Spectroscopy (XRF) was used to study 17th and 18th century Mexican, Potosí, and Massachusetts silver colonial coins from the University of Notre Dame’s Rare Books and Special Collections. Using different configurations and devices, we have learned more about the limitations and optimizations of the method. We have developed a moveable stand that may be used for XRF mapping of coin surfaces. We created standard silver alloy materials for quantification of the elemental composition of the coins. Inductively coupled plasma (ICP) spectroscopy was applied to determine the precise composition of the standards for accurate and non-destructive analyses of the colonial coins. XRF measurements were performed using two different XRF spectrometers, in both air and vacuum conditions, as well as an x-ray beam tube of varying diameters from 2 mm, 1 mm, and 0.03 mm. We quantified both the major elements and the bulk and surface impurities for 90 coins. We are using PCA to look at possible correlations between compositions of coinage from different geographical regions. Preliminary data analyses suggest that Massachusetts coins were minted using silver from Latin American sources. These results are of great interest to historians in tracing the origins of the currency.   

Multiscale Pigment Analysis of Medieval Illuminated Manuscripts

Three medieval illuminated manuscripts (codd. Lat. b. 1; Lat. b. 2; Lat. e. 4), housed at the University of Notre Dame's Hesburgh Library, vary in style, pigments, scribes, and regions, despite all three being Psalters used in the Late Middle Ages. XRF and Raman spectroscopy, which provided the elemental and molecular composition of the pigments, respectively, were used to analyze the pigments' compositions in an attempt to narrow further the manuscripts' possible origins. This experimental investigation emphasizes the importance of understanding the history of the manuscript through their pigments. Codd. Lat. b. 1 and Lat. b. 2 are Latinate German Psalters from the fifteenth century likely used in Katharinenkloster in Nuremberg. While there are visible differences in style within each Psalter, the variations in some of the pigment compositions, such as the inconstant presence of zinc, suggest different admixtures. Cod. Lat. e. 4 is a Latinate English Psalter from the fourteenth century, and it was written by two scribes and illuminated by two distinct painters. It is currently being tested to determine whether there are any correlations between the scribes and painters. These physical analyses will clarify the origins and provenances of the manuscripts.   

Forgery at the Snite Museum of Art? Improving AMS Radiocarbon Dating at the University of Notre Dame

The Snite Museum of Art recently obtained several donations of artifacts. Five of the pieces lack sufficient background information to prove authenticity and require further analysis to positively determine the artwork's age. One method to determine the artwork's age is radiocarbon dating via Accelerator Mass Spectrometry (AMS) performed at the University of Notre Dame's Nuclear Science Laboratory. Samples are prepared by combustion of a small amount of material and subsequent reduction to carbon into an iron powder matrix (graphitization). The graphitization procedure affects the maximum measurement rate, and a poor graphitization can be detrimental to the AMS measurement of the sample. Previous graphitization procedures resulted in a particle current too low or inconsistent to optimize AMS measurements. Thus, there was a desire to design and refine the graphitization system. The finalized process yielded physically darker samples and increased sample currents by two orders of magnitude. Additionally, the first testing of the samples was successful, yet analysis of the dates proved inconclusive. AMS measurements will be performed again to obtain better sampling statistics in the hopes of narrowing the reported date ranges.   

The Effects of the Softness of ``Off-Shell'' Nuclei on Nuclear Incompressibility

The nuclear incompressibility is a key parameter governing the nuclear matter equation of state, which is important in the study of type-II supernova explosion and the radii of neutron stars. To experimentally constrain this quantity, we study the compressional mode giant resonances, namely, the isoscalar giant monopole resonance (ISGMR). It has been revealed in recent years that theoretical models which are calibrated to reproduce the ISGMR strength distribution in standard and doubly-closed nuclei underestimate the incompressibility for off-shell nuclei, resulting in the off-shell nuclei being termed "soft". This research focused on the study of the $_{\mathrm{94,96,97,98,100}}$Mo isotopic chain for a systematic observation on how the "softness" manifests itself. The experiment was performed at the Research Center of Nuclear Physics, Osaka University and inelastic scattering of alpha particles was measured at extremely forward angles to provide maximal cross sections for exciting ISGMR. By measuring the ISGMR strength distributions in the aforementioned isotopes, we aim to observe the systematic effect on nuclear incompressibility and answer when does this ``softness" appear in moving away from closed shells, and how it develops.   

Analysis of Phase-Imaging Ion-Cyclotron-Resonance Mass Measurements at Argonne National Lab

In the realm of nuclear physics, the well-known method of adding up the protons, neutrons, and electrons falls short of giving the true mass of the atom, neglecting the binding energy of the nucleus. Thus, further studies into nuclear structure are warranted, and are especially relevant for nuclear astrophysics in the study of the r-process. The primary contemporary tool for determining the mass of an ion with high precision is the Penning trap. One of the newest methods for increasing the precision of Penning trap mass measurements is known as the Phase-Imaging technique. Using this technique, the measurement of nuclear masses is accomplished by measuring the cyclotron frequency of the isotopes circling within the trap. Using time-dependent position measurements, the phases of the circling ions are used to determine the cyclotron frequency and, subsequently, the nuclear mass. I will report on the measurements of several neutron rich nuclear masses in the rare earth region from Argonne National Lab's Canadian Penning Trap facility.   

Detailed characterization of low background $\beta $-delayed proton detector

In order to determine the rates of two important reactions for the astrophysical rapid proton (rp) capture process, a segmented, low background $\beta $-delayed proton detector has been built at NSCL. The detector is currently in the process of being optimized. A detailed characterization of the detector's Micromegas pad plane is being performed using measurements with a radioactive $^{\mathrm{55}}$Fe x-ray calibration source. A fitting routine has been developed to extract the energy resolution from the spectra. First results of detector resolution with P10 gas will be presented.   

Optical Thin Film Thickness Measurement for the Single Atom Microscope

The Single Atom Microscope Project proposes an efficient, selective, and sensitive method to measure the $^{22}_{10}Ne + ^{4}_{2}He -> ^{25}_{12}Mg + n$ reaction. This rare nuclear reaction is a source of neutrons for heavy element development through the slow neutron capture process. This method embeds Magnesium atoms in a solid neon film. The Magnesium atoms exhibit a shifted fluorescence spectrum allowing for the detection of individual fluorescence photons against the excitation light background. Currently, Ytterbium is used in place of Magnesium-25 because it has been more thoroughly studied than Magnesium and we expect it to have a brighter signal. To identify the signal emitted from the Ytterbium atoms, we need to quantify the amount of signal and background per atom in the neon film. We need to know the film thickness to find the number of atoms in the film to determine the amount of light emitted per atom. In preparation for the neon film measurement, I constructed an experiment to advance the understanding of what is required to optically measure a thin film by using a cover glass slide in place of the thin film. This preliminary experiment has determined a measurement method for finding the thickness of a neon thin film on a sapphire substrate.   

Determination of Partial Cross Sections in Single Nucleon Knockout Reactions

The structure of nuclei can be studied with knockout reactions where a few nucleons are removed from the projectile. These reactions can be accurately modeled [1], therefore, the nuclear structure input can be tested by comparing to the experimental cross sections. One test of structure models are partial cross sections to individual states for single nucleon knockout reactions. Seven knockout reactions of $p$-shell nuclei were performed at the National Superconducting Cyclotron Laboratory (NSCL). CAESAR, a CsI scintillator array, was used to detect gamma-rays from the reaction products. To determine the ratio of the cross section to the excited states, the response of the gamma-rays in CAESAR was simulated and combined with a background function. These were fitted to the experimental spectra to count the number of gamma-rays emitted. Ratios of the cross section from the ground to excited state will be presented. Combined with previous inclusive cross section measurements of the same reactions, these result can yield the partial cross sections. [1] G.F. Grinyer \textit{et al.}, Phys. Rev. Lett. 106, 162502 (2011).?   

Simulating the Response of a New Beta Delayed Proton Detector

\\To better understand reactions of astrophysical importance, such as $^{15}$O($\alpha$,$\gamma$)$^{19}$Ne and $^{30}$P(p,$\gamma$)$^{31}$S, a new gas filled detector of $\beta$-delayed charged particles has been designed and built for use at the National Superconducting Cyclotron Laboratory. The detector has separate drift and proportional amplification regions provided by a flex-board field cage and a Micromegas structure, respectively. We have developed a simulation to model the response of this detector using Magboltz and Garfield++ which calculate the electron transport and amplification through the two regions. The simulation provides information that is useful for understanding the microscopic function of the detector and will help optimize its operation.\\   

SECAR: The SEparator for CApture Reactions in Nuclear Astrophysics

Recoil separators are used to directly measure the reaction rates of proton and alpha capture reactions that take place in stellar explosions (e.g., X-Ray Bursts, Novae, etc.). SECAR is a newly designed recoil separator at the National Superconducting Laboratory (NSCL) and eventually the Facility for Rare Isotope Beams (FRIB) designed to achieve the highest particle rejection rate yet, estimated at 10\textsuperscript{17} particles per beam, needed to mainly measure the rates relevant to novae and x-ray burst phenomena. As of now 21 out of the 27 magnets that make up SECAR have been delivered, tested, and accepted with the remaining magnets and Wien filters to be delivered in Fall 2017 and Spring 2018. This paper will discuss the motivation for SECAR, the process in which the separator is being implemented, the methods used to ensure that the magnets that make up SECAR will be able to perform at the desired specifications, including testing for magnetic field reproducibility and discuss how the plans for commissioning of the system.   

Constraining Calcium Production in Novae

Calcium is an element that can be produced by thermonuclear reactions in the hottest classical novae. There are discrepancies between the abundance of Calcium observed in novae and expectations based on astrophysical models. Unbound states 1 MeV above the proton threshold affect the production of Calcium in nova models because they act as resonances in the $^{38}K(p,\gamma)^{39}Ca$ reaction present. This work describes an experiment to measure the energies of the excited states of $^{39}Ca$. We will bombard a thin target of $^{40}Ca$ with a beam of 22 MeV deuterons, resulting in tritons and $^{39}$Ca. We will use a Q3D magnetic spectrograph from the MLL in Garching, Germany to momenta analyze the tritons to observe the excitation energies of the resulting $^{39}Ca$ states. Simulations have been run to determine the optimal spectrograph settings. We decided to use a chemically stable target composed of $CaF_2$, doing so resulted in an extra contaminant, Fluorine, which is dealt with by measuring the background from a LiF target. These simulations have led to settings and targets that will result in the observation of the $^{39}Ca$ states of interest with minimal interference from contaminants. Preliminary results from this experiment will be presented.   

Characterizing a Tape Station and $\beta$ Detector For Radioactive Isotope Beam Experiments

In order to better understand the nucleosynthesis of heavy elements, advanced techniques are needed to study decays of neutron-rich nuclei and to constrain astrophysical models. In conjunction with the Summing NaI(Tl) detector (SuN) at the NSCL, a tape station is being developed to optimize these measurements. A radioactive isotope beam will be implanted directly onto metallic tape at the center of SuN. The primary ions will $\beta$-decay toward stability, however radiation from the daughter nuclei presents a significant source of contamination. The tape rotates so that the implantation point moves into a shielded box outside of SuN to remove the contamination after a certain time. The timing depends on the half-life of the primary and daughter ions so a simulation was developed to determine effective timing parameters to use in each experiment. A new plastic scintillator will be used in conjunction with the tape to detect $\beta$ particles. Light from the plastic will be collected with wavelength shifting fibers that will be coupled to photomultiplier tubes outside of SuN. The status of the tape station, including the simulation and characterizing of the fiber detector will be discussed.   

Commissioning of a new photon detection system for charge radii measurements of neutron-deficient Ca

Calcium is unique for its possession of two stable isotopes of ``doubly magic" nuclei at proton and neutron numbers $(Z, N) = (20, 20)$ and $(20, 28)$. Recent charge radii measurements of neutron-rich calcium isotopes yielded an upward trend beyond current theoretical predictions [R. F. G. Ruiz et al., Nat. Phys. 12, 594 (2016)]. At the BECOLA facility at NSCL/MSU, Ca charge radii measurements will be extended to the neutron-deficient regime using collinear laser spectroscopy. A new photon detection system with an ellipsoidal reflector and a compound parabolic concentrator has been commissioned for the experiment. The system increases the signal-to-noise ratio by reducing background, which is critical for the low production rates of the Ca experiment. Details of the system and results of the characterization tests will be discussed.   

Computing wave functions in multichannel collisions with non-local potentials using the R-matrix method

The calculable form of the R-matrix method has been previously shown to be a useful tool in approximately solving the Schrodinger equation in nuclear scattering problems. We use this technique combined with the Gauss quadrature for the Lagrange-mesh method to efficiently solve for the wave functions of projectile nuclei in low energy collisions (~1-100 MeV) involving an arbitrary number of channels. We include the local Woods-Saxon potential, the non-local potential of Perey and Buck, a Coulomb potential, and a coupling potential to computationally solve for the wave function of two nuclei at short distances. Object oriented programming is used to increase modularity, and parallel programming techniques are introduced to reduce computation time. We conclude that the R-matrix method is an effective method to predict the wave functions of nuclei in scattering problems involving both multiple channels and non-local potentials.   

A streamlined Python framework for AT-TPC data analysis

User-friendly data analysis software has been developed for the Active-Target Time Projection Chamber (AT-TPC) experiment at the National Superconducting Cyclotron Laboratory at Michigan State University. The AT-TPC, commissioned in 2014, is a gas-filled detector that acts as both the detector and target for high-efficiency detection of low-intensity, exotic nuclear reactions. The pytpc framework is a Python package for analyzing AT-TPC data. The package was developed for the analysis of $^{46}$Ar(p, p) data. The existing software was used to analyze data produced by the $^{40}$Ar(p, p) experiment that ran in August, 2015. Usage of the package was documented in an analysis manual both to improve analysis steps and aid in the work of future AT-TPC users. Software features and analysis methods in the pytpc framework will be presented along with the $^{40}$Ar results.   

Experimentally Determining $\beta $-Decay Intensities for $^{\mathrm{103,104}}$Nb to Improve R-process Calculations

The rapid neutron capture process (r-process) is responsible for the formation of nuclei heavier than iron. This process is theorized to occur in supernovas and/or neutron star mergers. R-process calculations require the accurate knowledge of a significant amount of nuclear properties, the majority of which are not known experimentally. Nuclear masses, $\beta $-decay properties and neutron-capture reactions are all input ingredients into r-process models. This present study focuses on the $\beta $ decay of $^{\mathrm{103}}$Nb and $^{\mathrm{104}}$Nb. The $\beta $ decay of $^{\mathrm{103}}$Nb and $^{\mathrm{104}}$Nb, two nuclei found in the r-process, were observed at the NSCL using the Summing NaI (SuN) detector. An unstable beam implanted inside SuN. The $\gamma $ rays were measured in coincidence with the emitted electrons. The $\beta $-decay intensity function was then extracted. The experimentally determined functions for $^{\mathrm{103}}$Nb and $^{\mathrm{104}}$Nb will be compared to predictions made by the Quasi Random Phase Approximation (QRPA) model. These theoretical calculations are used in astrophysical models of the r-process. This comparison will lead to a better understanding of the nuclear structure for $^{\mathrm{103}}$Nb and $^{\mathrm{104}}$Nb. A more dependable prediction of the formation of heavier nuclei birthed from supernovas or neutron star mergers can then be made.   

Test of Monte Carlo Simulation for MoNA neutron detectors

The MoNA (Modular Neutron Array) and LISA (Large multi-Institutional Scintillator Array) detector systems at NSCL are used to determine the energy and trajectory of neutrons decaying from particle-unbound states in exotic neutron-rich nuclei. In order to test the accuracy of simulation (GEANT4 with Menate\_R), important for interpreting scattering data from the arrays, an experiment was recently conducted at Los Alamos LANSCE center using 16 MoNA detectors (each consisting of BC408 organic scintillator plastic measuring 200x10x10 cm$^3$) exposed to a thin, well-characterized neutron beam over a wide energy range in order to observe neutron scattering directly. Neutrons scatter elastically from H and C nuclei and inelastically from C nuclei. Elastic scattering from C (including some inelastic channels) produce light below detector threshold, and therefore constitute ``dark scattering,'' redirecting neutron trajectories without detection, and some inelastic C channels produce additional neutrons in the array. Several features of scattering, including scattering angle, mean distance between scatters, multiplicity, and dark-scatter redirection are analyzed and compared with simulation over a wide range of incoming neutron energy. Results will be presented.   

Charged Particle Identification for Prefragmentation Studies

Projectile fragmentation refers to high energy (>50MeV/u) heavy ion beams on production targets to generate intermediate mass and target fragments at facilities like the NSCL, FRIB, GSI, GANIL and RIKEN. The resulting secondary beams can then be isolated by fragment separators like the NCSL's A1900 and that secondary beam then used on reaction targets for a variety of experiments. Predictions of beam intensities for experiment planning depend on models and data. The MoNA Collaboration performed an experiment at the NSCL in which a $^{48}$Ca primary beam was used with a $^{9}$Be target to produce a $^{32}$Mg secondary beam with energy 86 MeV/u that was incident on a second target of $^{9}$Be. By characterizing the energy distributions of final fragments of neon, sodium, and fluorine in coincidence with neutrons created both by prefragmentation processes and reaction mechanisms, we are able to extract information about prefragmentation dynamics. The identification of charged fragments is a multi-step process crucial to this analysis.   

Sequential Decay of ${ }^{26}$F

Unstable neutron rich nuclides show interesting characteristics including multi-neutron emission. By using Jacobi coordinates, multi-neutron emissions from unstable nuclides may be characterized. At the National Superconducting Cyclotron Laboratory experiment, a 101.3 MeV/u ${ }^{27}$Ne ion beam hit a liquid deuterium target, causing reactions which produced several nuclides. Many of these nuclides decayed, resulting in a charged fragment and one or more neutrons. A superconducting dipole magnet bent the path of the fragments into a series of charged-particle detectors. Neutrons from these decays were measured as they interacted with arrays of scintillating plastic bars called the MoNA-LISA. The four-momentum vectors of the charged particle and neutron(s) were used to reconstruct the invariant mass. ${ }^{26}$F was formed by 1-proton stripping from the ${ }^{27}$Ne beam, which resulted in either one or two neutrons emission. A GEANT4 simulation comparison to the experimental data shows that sequential neutron emission resulted from some of the ${ }^{26}$F produced. The results of these comparisons will be presented.   

Investigating the Inversion of $^{9}$He

The one-neutron unbound $^9$He nucleus is in a region of the nuclear chart, the light island of inversion, where the ground-state structure is expected to be inverted relative to the typical shell model structure: the inverted ground state is expected to be a 1/2$^{+}$ state indicating that the valence neutron is in the s$_{1/2}$ orbital, in comparison to the standard shell model structure which would suggest a 1/2$^{-}$ state due to the valence p$_{1/2}$ neutron. Past experiments have struggled to provide a consistent and accurate picture of the (energy) level structure of $^9$He. One of the difficulties of previous experiments is that the reactions have populated mainly one state and therefore were unable to simultaneously constraint both states. Experiment e15091 was conducted in the summer 2017 to measure the invariant mass spectrum of $^9$He from two different reactions: $^{11}$Be(-2p) and $^{12}$B(-3p). The $^{11}$Be reaction strongly populates the 1/2$^+$ state while the $^{12}$B reaction strongly populates the 1/2$^{-}$ state. The experiment used the MoNA-LISA-Sweeper setup of the National Superconducting Cyclotron Laboratory (NSCL) in Lansing, Michigan. Preliminary analysis of the data, including detector calibration and particle identification, will be presented.   

Neutron Radioactivity in $^{\mathrm{26}}$O and Lifetime Analysis of Neutron-Rich Isotopes

Currently there is only one known isotope that is likely to exhibit two-neutron radioactivity. This unique occurrence is found when observing neutron-rich $^{\mathrm{26}}$O. This isotope of oxygen is particularly interesting because early experiments show it living significantly longer than nearby isotopes . In order to gain a better understanding of neutron radioactivity, the MoNA Collaboration is working on determining the lifetime of $^{\mathrm{26}}$O. To experimentally deduce the lifetime, the change in energy during the emission of neutrons from the $^{\mathrm{26}}$O nucleus is being measured. A $^{\mathrm{27}}$F beam was accelerated into a beryllium target, and a variety of interactions occurred. In the case of one-proton removal, $^{\mathrm{26}}$O was formed. Two neutrons are then emitted from $^{\mathrm{26}}$O, and the MoNA and LISA detectors are used to measure the velocity of the neutrons. This velocity is compared to the velocity of the fragment $^{\mathrm{24}}$O. The relative velocity can be used to find the lifetime of $^{\mathrm{26}}$O. Learning about this lifetime will provide valuable information about neutron-rich isotopes and give more insight into two-neutron radioactivity.   

First Observation of Three-Neutron Sequential Emission from $^{\mathrm{25}}$O

An active area of nuclear physics research is to evaluate models of the nuclear force by studying the structure of neutron-rich isotopes. In this experiment, a 101.3 MeV/u $^{\mathrm{27}}$Ne beam from the National Superconducting Cyclotron Laboratory collided with a liquid deuterium target. The collision resulted in two-proton removal from the $^{\mathrm{27}}$Ne beam which created excited $^{\mathrm{25}}$O that decayed into three neutrons and an $^{\mathrm{22}}$O fragment. The neutrons were detected by arrays of scintillating plastic bars, while a 4-Tesla dipole magnet placed directly after the target redirected charged fragments to a series of charged-particle detectors. From measured velocities of the neutrons and $^{\mathrm{22}}$O fragments, the decay energy of $^{\mathrm{25}}$O was calculated on an event-by-event basis with invariant mass spectroscopy. Using GEANT4, we simulated the decay of all nuclei that could have been created by the beam collision. By successfully fitting simulated decay processes to experimental data, we determined the decay processes present in the experiment.   

Neutron Scattering in MoNA detector bars for Comparison with Simulation

In order to test the effectiveness and accuracy of Monte Carlo simulation (GEANT4 with Menate\_R), used by the MoNA collaboration for interpreting neutron-scattering data from the MoNA (Modular Neutron Array) and LISA (Large multi-Institutional Scintillator Arrays at NSCL, MSU, an experiment was conducted at Los Alamos LANSCE center in which 16 MoNA detector bars were exposed to a well characterized neutron beam. Each MoNA bar consists of BC408 organic scintillator measuring 200x10x10 cm$^3$ with PMTs attached to each end. In order to properly characterize important neutron scattering signatures over a wide range of incoming neutron energy, such as scattering angle, mean distance between scatters, multiplicity, and dark-scatter, it is important that background be fully understood and corrected for. Background sources include neutrons scattered from the collimator on entrance to the room, decay of neutron-activation within the bars, neutrons scattering in the room, and cosmic muons. Several methods for accounting for and removing background contributions to data were developed so that data can be compared directly with simulation (which does not contain these background features). Results, including scattering data comparisons with simulation will be presented.   

Inverse-kinematics proton scattering from $^{41}$P

We have measured the gamma-ray spectrum of $^{41}$P using proton scattering in inverse kinematics with the NSCL/Ursinus College liquid hydrogen target and the GRETINA gamma-ray tracking array. We present preliminary results, including cross sections for populating several excited states of $^{41}$P via proton scattering.   

Inverse-kinematics proton scattering from $^{43}$P

Following an experiment at the National Superconducting Cyclotron Laboratory at Michigan State University (NSCL) in October 2016, we study the excited states of the neutron-rich $N=28$ isotope $^{43}$P via inverse-kinematic proton scattering with the GRETINA gamma-ray tracking array and the NSCL/Ursinus College liquid hydrogen target. We discuss preliminary analysis and results, including measured cross sections for populating excited states of $^{43}$P.   

A nonlocal application of the dispersive optical model to $^{\mathrm{208}}$Pb

A nonlocal application of the dispersive optical model to neutrons and protons in $^{\mathrm{208}}$Pb is presented. A nucleon self-energy is described by parametrized real and imaginary parts connected through a dispersion relation. This parametrization includes nonlocal Hartree-Fock and local Coulomb and spin-orbit real terms, and nonlocal volume and surface and local spin-orbit imaginary terms. A simple Gaussian nonlocality is employed, and appropriate asymmetry parameters are included to describe the N-Z dependence of the nucleus. These parameters are constrained by fitting to experimental data, including particle numbers, energy levels, the charge density, elastic-scattering angular distributions, reaction cross sections, and the neutron total reaction cross section. From the resulting nucleon self-energy, the neutron matter distribution and neutron skin are deduced.   

Monte Carlo simulations for a carbon-14 beta spectrum measurement

The Conserved Vector Current (CVC) hypothesis of the standard model of the electroweak interaction predicts there is a linear contribution to the shape of the spectrum in the beta-minus decay of 14C. In order to provide a strong test of the CVC hypothesis, measurements of the 14C decay spectrum will be taken using a magnetic spectrometer. Scattering in the source material and from the supporting Be foil will lead to distortions of the measured spectrum, especially since the 14C radiation is so low in energy (156 keV endpoint). Simulations in both EGSnrc and Geant4 radiation transport software are being constructed to model the scattering effects and correct for distortion in the observed beta spectrum.   

Design of a Prototype Single Atom Microscope for Nuclear Astrophysics

We are designing and building a prototype Single Atom Microscope (pSAM) in order to demonstrate optical single atom detection in thin films of solid neon. Once our single atom detection technique has been demonstrated, the prototype will be upgraded to SAM, which will be designed for nuclear physics measurements. Specifically, SAM will be coupled with a recoil separator to discriminate between isotopes and to reduce the heat load on the neon, with a long term goal of measuring the $^{\mathrm{22}}$Ne($\alpha $,n)$^{\mathrm{25}}$Mg reaction, an important source of neutrons for the s-process. This technique has the potential to capture and detect every product atom with near unity efficiency. In order to achieve this goal, pSAM has been designed to freeze neon at 4.2 K, maximize the light collection efficiency, minimize impurities in the vacuum, and provide repeatable measurements. I will describe the pSAM setup in more detail, focusing on how we addressed these technical challenges in the design. This work is supported by Michigan State University, the Director's Research Scholars Program at the National Superconducting Cyclotron Laboratory, and U.S. National Science Foundation under grant number {\#}1654610.   

Parity Measurements in $^{70}$Ge

Previous studies of the $^{70}$Ge nucleus have left open questions about its decay spectrum, in particular the spins and parities of the high-spin states. The goal of this work was thus to measure the parity of as many states in $^{70}$Ge as possible. High-spin states in $^{70}$Ge were produced from the $^{62}$Ni($^{14}$C,$\alpha 2n$) reaction at 50 MeV performed at Florida State University. The resulting $\gamma$ decays were measured in coincidence using a Compton-suppressed Ge array consisting of three Clover detectors and seven single-crystal detectors. The parallel and perpendicular Compton-scattering yields in a Clover detector (relative to the beam direction) were measured under the condition that another $\gamma$ decay in $^{70}$Ge was also detected in coincidence. Ultimately, the linear polarizations of eight transitions in $^{70}$Ge were measured, leading to the confirmation of eight parity assignments. In general, the linear polarization measurements for the low-spin transitions show good agreement with those measured previously as well as with theoretical predictions based on previous angular distribution measurements.   

Parity Measurements in the $^{70}$Ga Nucleus

The odd-odd $^{70}$Ga nucleus was studied at high spin after being produced at Florida State University using the $^{62}$Ni($^{14}$C, $\alpha pn$) fusion-evaporation reaction at a beam energy of 50 MeV. The resulting $\gamma$ rays were detected in coincidence using an array of Compton-suppressed Ge detectors consisting of three Clover detectors and seven single-crystal detectors. The linear polarizations of eight $\gamma$-ray transitions in $^{70}$Ga were measured by comparing their scattering yields within a Clover detector in the parallel and perpendicular directions relative to the beam axis, under the requirement that at least one other $\gamma$ ray in $^{70}$Ga was recorded by a single-crystal detector in the array. As a result of these measurements, the parities of six states were confirmed and those of two other states were established for the first time based on a comparison of the experimental polarizations with the predicted ones determined from known spin assignments. The resulting level spectrum of $^{70}$Ga shows both similarities and differences with the predictions of previous shell-model calculations.   

High-precision gamma-ray spectroscopy of 61Cu, an emerging medical isotope used in positron emission tomography

$^{61}$Cu ($t_{1/2}$ = 3.339h) is an important medical isotope used in positron emission tomography (PET) tumor hypoxia imaging scans; however, its beta-plus decay and the subsequent gamma decay of $^{61}$Ni has not been studied in over 30 years. Therefore, high quality decay data of $^{61}$Cu is desired to determine the overall dose delivered to a patient. In this study, $^{61}$Cu was produced at the University of Wisconsin - Madison cyclotron and then assayed using the Gammasphere array at Argonne National Laboratory. Consisting of 70 Compton-suppressed high-purity germanium (HPGe) detectors, Gammasphere provides precise decay data that exceeds that of previous $^{61}$Cu studies. $\gamma$-ray singles and coincident data were recorded and then analyzed using Radware gf3m software. Through $\gamma$-$\gamma$ coincidence techniques, new $\gamma$-ray transitions were identified and high precision determination of $\gamma$-ray intensities were made. These modifications and additions to the current decay scheme will be presented, and their impact on the resulting does estimates will be discussed.   

Nuclear structure studies of $^{\mathrm{141}}$Ce and $^{\mathrm{147}}$Sm using deep-inelastic collisions

Nuclei with a few valence nucleons outside of the magic numbers are essential for testing the nuclear shell model and gathering information on the residual interactions and energies of single-particle levels. The present work focused on the high-spin structures of $^{\mathrm{141}}$Ce (N $=$ 83) and $^{\mathrm{147}}$Sm (N $=$ 85). These nuclei are not produced by heavy-ion fusion-evaporation or fission reactions, therefore little was known about their high-spin structure. A deep-inelastic reaction using a beam of $^{\mathrm{136}}$Xe incident on a thick target of $^{\mathrm{208}}$Pb was used to populate excited states in the nuclei. The Gammasphere array at Argonne National Laboratory was used to detect the resulting de-excitation -ray transitions. The level schemes of both nuclei were significantly extended to high angular momentum and high excitation energy. In $^{\mathrm{141}}$Ce, this included a number of states built on the i$_{\mathrm{13/2}}$, 1369-keV level. Results of the present analysis will be compared to state-of-the-art shell model calculations.   

Measurement of 47K Half-Life at GRIFFIN

The doubly magic nucleus $^{48}$Ca is both a neutron-rich benchmark for new \textit{ab initio} nuclear structure calculations and a potential neutrinoless double beta decay parent. The adjacent decay of $^{47}$K to $^{47}$Ca is a simpler decay, but requires a more robust nuclear structure calculation. TRIUMF's GRIFFIN (Gamma Ray Infrastructure For Fundamental Investigations of Nuclei) array is a set of 16 HPGe clovers at the ISAC-I accelerator. This setup allows for the analysis of short-lived isotopes by delivering them to GRIFFIN shortly after their production in ISAC-I and measuring their decay radiation with GRIFFIN and associated auxiliary detectors. This poster presents the use of GRIFFIN, with the additional SCEPTAR (SCintillating Electron-Positron Tagging ARray) auxiliary detector, to improve the precision of the half-life of $^{47}$K as part of a more detailed decay spectroscopy investigation.   

Elastic and inelastic neutron scattering cross sections for $^{\mathrm{12}}$C at E$_{\mathrm{n}}=$5.9, 6.1, and 7.0 MeV

Measurements of neutron elastic and inelastic scattering differential cross sections from $^{\mathrm{12}}$C have been performed at incident neutron energies of 5.9, 6.1, and 7.0 MeV. Comparisons of existing experimental cross sections (NNDC) at these incident neutron energies reveal large discrepancies. Accurate measurements of $^{\mathrm{12}}$C cross sections are vital to facilitate precise calculations regarding criticality conditions for nuclear reactors, advances in security screening methods, and better understanding astrophysical and nuclear phenomenon. During preliminary measurements of $^{\mathrm{12}}$C cross sections at the University of Kentucky Accelerator Laboratory (UKAL), we realized the relative efficiency of the deuterated benzene (main) detector was needed over an unusually large range of neutron energies due to the high Q value of the first excited state of $^{\mathrm{12}}$C. Those experiments were repeated during the summer of 2017 to measure \textit{in situ} the relative detector efficiency with better beam conditions and a better understanding of background observed from the $^{\mathrm{2}}$H(d, n)$^{\mathrm{3}}$He source reaction. The resulting improved detector efficiency was used in determining the neutron elastic and inelastic scattering cross sections. While the former were found to be in excellent agreement with evaluated cross sections from ENDF, the latter show some discrepancies, especially at 6.1 MeV. Our results will be presented.   

Neutron elastic and inelastic cross section measurements for $^{\mathrm{28}}$Si

Neutron elastic and inelastic cross sections are critical for design and implementation of nuclear reactors and reactor equipment. Silicon, an element used abundantly in fuel pellets as well as building materials, has little to no experimental cross sections in the fast neutron region to support current theoretical evaluations, and thus would benefit from any contribution. Measurements of neutron elastic and inelastic differential scattering cross sections for $^{\mathrm{28}}$Si were performed at the University of Kentucky Accelerator Laboratory for incident neutron energies of 6.1 MeV and 7.0 MeV. Neutrons were produced by accelerated deuterons incident on a deuterium gas cell. These nearly mono-energetic neutrons then scattered off a natural Si sample and were detected using liquid deuterated benzene scintillation detectors. Scattered neutron energy was deduced using time-of-flight techniques in tandem with kinematic calculations for an angular distribution. The relative detector efficiency was experimentally determined over a neutron energy range from approximately 0.5 to 7.75 MeV prior to the experiment. Yields were corrected for multiple scattering and neutron attenuation in the sample using the forced-collision Monte Carlo correction code MULCAT. Resulting cross sections will be presented along with comparisons to various data evaluations.   

Non-Local Translationally Invariant Nuclear Density

Nonlocal nuclear density is derived from the no-core shell model (NCSM) one-body densities by generalizing the local density operator to a nonlocal form. The translational invariance is generated by exactly removing the spurious center of mass (COM) component of the harmonic oscillator wavefunctions. This enables the ab initio NCSM nuclear structure to be used in high energy nuclear reactions and density functional theory. The ground state local and nonlocal density of Helium-4, Helium-6, Helium-8, and Oxygen-16 are calculated to display the effects of COM removal on predicted nuclear structure. We show that amplified effects of the COM removal can be seen in related quantities like kinetic density, which is dependent on gradients of the nonlocal nuclear density. Additionally, we include nonlocal density in calculations of optical potentials -- as opposed to using the local approximation -- which produces more accurate theoretical predictions for the optical potentials of lighter nuclei. We present differential cross sections and analyzing powers for proton scattering on Helium-4, Helium-6, Helium-8, and Oxygen-16 at high energies using modern nucleon-nucleon and three-nucleon chiral interactions.   

Measuring the Neutron Cross Section and Detector Response from Interactions in Liquid Argon

The main objective of the CAPTAIN (Cryogenic Apparatus for Precision Tests of Argon Interactions with Neutrinos) program is to measure neutron and neutrino interactions in liquid argon. These results will be essential to the development of both short and long baseline neutrino experiments. The full CAPTAIN experiment involves a 10 ton liquid argon time projection chamber (LArTPC) that will take runs at a low-energy (\textasciitilde 10-50 MeV) stopped pion neutrino source. A two ton LArTPC, MiniCAPTAIN, will serve as a prototype for the full CAPTAIN detector. MiniCAPTAIN has been deployed to take data at the Los Alamos Neutron Science Center in late July. During this run, it will both test new LArTPC technologies and measure the cross section and detector response of neutron interactions in liquid argon. The results will be helpful in characterizing neutral current neutrino interactions and identifying background in future neutrino detection experiments. This poster gives an overview of these results and a status update on the CAPTAIN collaboration.~   

Forward Propagation Analysis for determining the 16O(n,alpha)13C Reaction Cross Section at LANSCE.

Oxygen is present in many materials and the uncertainties in its nuclear data can have a significant impact on applications. In particular, neutron-absorption reactions reduceavailable neutrons in applications. Thus,high precision in knowledge of this reaction cross sectionis required. To decreasethe systematic uncertainty, we developed a framework that uses Forward Propagation Analysis (FPA) for determining the 16O(n,a)13C reaction cross section from data measured at LANSCE. The Low Energy NZ (LENZ) instrument was used to detectreaction alphas on the Ta2O5 solid target with silicon strip detectors. The FPA was performed in GEANT4. The geometry, efficiency, and resolution functions of LENZ werevalidated by comparing with the alpha emitting Th-229 source measurement. To reproduce experimental yields in silicon strip detectors, the energy dependent neutron beam flux distribution, the 16O(n,a) reaction differential cross sections, and the 2-body kinematics calculations were implemented in the simulation. We present results from the FPA on LENZ data anddiscuss the improved data analysis [LA-UR-17-26436].   

Actinide Sputtering Induced by Fission with Ultra-cold Neutrons

Understanding the effects of actinide sputtering due to nuclear fission is important for a wide range of applications, including nuclear fuel storage, space science, and national defense. A new program at the Los Alamos Neutron Science Center uses ultracold neutrons (UCN) to induce fission in actinides such as uranium and plutonium. By controlling the energy of UCN, it is possible to induce fission at the sample surface within a well-defined depth. It is therefore an ideal tool for studying the effects of fission-induced sputtering as a function of interaction depth. Since the mechanism for fission-induced surface damage is not well understood, especially for samples with a surface oxide layer, this work has the potential to separate the various damage mechanisms proposed in previous works. During the irradiation with UCN, fission events are monitored by coincidence counting between prompt gamma rays using NaI detectors. Alpha spectroscopy of the ejected actinide material is performed in a custom-built ionization chamber to determine the amount of sputtered material. Actinide samples with various sample properties and surface conditions are irradiated and analyzed. In this presentation, we will discuss our experimental setup and present the preliminary results.   

Monitoring the Gas Composition of the NIFFTE Time Projection Chamber

The Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) at Los Alamos National Laboratory(LANL) is using a Time Projection Chamber (TPC) to measure with high precision the cross section ratio of U238 to P239. When the neutron beam hits a target, it may emit fission fragments. As the fission fragments travels through the chamber, it ionizes the gas it passes through. Based on the time it takes for the ions to drift to the pad planes and the hit location of the ions, the path of fission fragments can be determined. Knowing the composition of the gas mixture is vital to accurately reconstruct the data. A Binary Gas Analyzer (BGA) is used to measure the gas composition. To confirm the accuracy of the BGA, varying amounts of nitrogen and carbon dioxide were flowed through a test gas system. Several tests were performed to validate that the BGA for our gas system is working properly. This poster will describe the test gas system setup, tests of the BGA, and elaborate on the main goals of the NIFFTE experiment.   

Neutron Dark-Field Imaging

Neutron imaging is typically used to image and reconstruct objects that are difficult to image using X-Ray imaging techniques. X-Ray absorption is primarily determined by the electron density of the material. This makes it difficult to image objects within materials that have high densities such as metal. However, the neutron scattering cross section primarily depends on the strong nuclear force, which varies somewhat randomly across the periodic table. In this project, an imaging technique known as dark field imaging using a far-field interferometer has been used to study a sample of granite. With this technique, interferometric phase images are generated. The dispersion of the microstructure of the sample dephases the beam, reducing the visibility. Collecting tomographic projections at different autocorrelation lengths (from 100~nanometers to 1.74~micrometers) essentially creates a 3D small angle scattering pattern, enabling mapping of how the microstructure is distributed throughout the sample.   

Fabrication, Quality Assurance, and Quality Control for PROSPECT Detector Component Production

The Precision Reactor Oscillation and Spectrum Experiment (PROSPECT) is an electron antineutrino ($\bar{\nu_e}$) detector intended to make a precision measurement of the $^{235}$U neutrino spectrum and to search for the possible existence of sterile neutrinos with a mass splitting of $\Delta m^2$ on the order of 1 $eV^2$. As a short baseline detector, PROSPECT will be located less than 10 meters from the High Flux Isotope Reactor at Oak Ridge National Laboratory. As PROSPECT intends to search for baseline-dependent oscillations, physical segmentation is needed to better measure the interaction position. PROSPECT will therefore be a segmented detector in two dimensions, thereby improving position measurements. PROSPECT will be segmented into 154 (11x14) 1.2-meter long rectangular tubes, using optical separators. Each separator will consist of a carbon fiber core, laminated with optical reflector (to increase light collection) and Teflon (to ensure compatibility with the scintillator). These optical separators will be held in place via strings of 3D printed PLA rods called “pinwheels.” This poster discusses the fabrication and quality assurance (QA) procedures used in the production of both the PROSPECT optical separators and pinwheels.   

Prospects for Improved Isotopic Reactor Antineutrino Flux Measurement

Recent reactor antineutrino experiments have observed a deficit in the antineutrino flux coming from nuclear reactors. Now referred to as the `Reactor Antineutrino Anomaly', this deficit might be caused by a miscalculation of the antineutrino flux from the decay of one or more of the fission isotopes namely $^{\mathrm{235}}$U, $^{\mathrm{238}}$U, $^{\mathrm{239}}$Pu and $^{\mathrm{241}}$Pu in nuclear reactors. This analysis looks at how well we can use current experiments results to determine the antineutrino flux coming from each of the fission isotopes and their contribution to the measured deficit. New short-baseline reactor neutrino efforts can produce unique new flux measurements that can improve constraints on isotopic antineutrino flux contributions beyond those enabled by existing flux measurements conducted over the past three decades. In particular, having the same detector placed at an HEU (Highly Enriched Uranium) and then at an LEU (Low Enriched Uranium) reactor will produce a series of highly-correlated antineutrino flux measurements. This poster will present future achievable constraints on isotopic contributions to the reactor antineutrino flux enabled by the addition of flux measurements at HEU and LEU reactor cores.   

Impact of Fission Neutron Energies on Reactor Antineutrino Spectra

Recent measurements of the reactor antineutrino spectra (Double Chooz, Reno, and Daya Bay) have shown a discrepancy in the 5-7 MeV region when compared to current theoretical models (Vogel and Huber-Mueller). There are numerous theories pertaining to this antineutrino anomaly, including theories that point to new physics beyond the standard model. In the paper ``Possible Origins and Implications of the Shoulder in Reactor Neutrino Spectra'' by A. Hayes et al., explanations for this anomaly are suggested. One theory is that there are interactions from fast and epithermal incident neutrons which are significant enough to create more events in the 5-7 MeV by a noticeable amount. In our research, we used the Oklo software network created by Dan Dwyer. This generates ab initio antineutrino and beta decay spectra based on standard fission yield databases ENDF, JENDL, JEFF, and the beta decay transition database ENSDF-6. Utilizing these databases as inputs, we show with reasonable assumptions one can prove contributions of fast and epithermal neutrons is less than 3{\%} in the 5-7 MeV region. We also discovered rare isotopes are present in beta decay chains but not well measured and have no corresponding database information, and studied its effect onto the spectrum.   

PIXE Analysis of Artificial Turf

In recent years, there has been debate regarding the use of the crumb rubber infill in artificial turf on high school and college campuses due to the potential presence of heavy metals and carcinogenic chemicals. We performed Proton-Induced X-Ray Emission (PIXE) analysis of artificial turf infill and blade samples collected from high school and college campuses around the Capital District of NYS to search for potentially toxic substances. Crumb rubber pellets were made by mixing 1g of rubber infill and 1g of epoxy. The pellets and the turf blades were bombarded with 2.2 MeV proton beams from a 1.1-MV tandem Pelletron accelerator in the Union College Ion-Beam Analysis Laboratory and x-ray energy spectra were collected with an Amptek silicon drift detector. We analyzed the spectra using GUPIX software to determine the elemental concentrations of the samples. The turf infill showed significant levels of Ti, Fe, Co, Ni, Cu, Zn, Br, and Pb. The highest concentration of Br in the crumb rubber was 1500 \textpm 100 ppm while the highest detectable amount of Pb concentration was 110 \textpm 20 ppm. The artificial turf blades showed significant levels of Ti, Fe, and Zn with only the yellow blade showing concentrations of V and Bi.   

Proton Induced X-Ray Emission (PIXE) Analysis to Measure Trace Metals in Soil Along the East River in Queens, New York

The Union College Ion-Beam Analysis Lab's 1.1 MV tandem Pelletron accelerator is used to determine the presence of heavy trace metals in Queens, NY between Astoria Park and 3.5 miles south to Gantry State Park. A PIXE analysis was performed on 0.5 g pelletized soil samples with a 2.2 MeV proton beam. The results show the presence of elements ranging from Ti to Pb with the concentration of Pb in Astoria Park (2200 \textpm 200 ppm) approximately ten times that of the Gantry State Park. We hypothesize that the high lead concentration at Astoria Park is due to the nearby Hell Gate Bridge, painted in 1916 with lead based paint, then sandblasted and repainted in the '90s. If the lead is from the repair of the bridge, then we should see the concentration decrease as we go further from the bridge. To test this, soil samples were collected and analyzed from seven different locations north and south of the bridge. The concentrations of lead decreased drastically within a 500 m radius and were approximately constant at greater distances. More soil samples need to be collected within the 500 m radius from bridge to identify the potential source of Pb. We will describe the experimental procedure, the PIXE analysis of soil samples, and present preliminary results on the distribution of heavy trace metals.   

Understanding Uncertainties and Biases in Jet Quenching in High-Energy Nucleus-Nucleus Collisions

Jets are the collimated streams of particles resulting from hard scattering in the initial state of high-energy collisions. In heavy-ion collisions, jets interact with the quark-gluon plasma (QGP) before freezeout, providing a probe into the internal structure and properties of the QGP. In order to study jets, background must be subtracted from the measured event, potentially introducing a bias. We aim to understand quantify this subtraction bias. PYTHIA, a library to simulate pure jet events, is used to simulate a model for a signature with one pure jet (a photon) and one quenched jet, where all quenched particle momenta are reduced by the same fraction. Background for the event is simulated using multiplicity values generated by the TRENTO initial state model of heavy-ion collisions fed into a thermal model from which to sample particle types and a 3-dimensional Boltzmann distribution from which to sample particle momenta. Data from the simulated events is used to train a statistical model, which computes a posterior distribution of the quench factor for a data set. The model was tested first on pure jet events and later on full events including the background. This model will allow for a quantitative determination of biases induced by various methods of background subtraction.   

Gamma spectroscopy with neutron spectroscopy around N$=$50, 82

Nuclear beta-decay presents a selective probe to study the daughter nucleus, where this selectivity can be exploited to study the properties of states involving specific single-particle orbits. Neutron single-hole orbitals in $^{\mathrm{133}}$Sn were studied in the beta-decay of $^{\mathrm{133}}$In at the ISOLDE facility, CERN. Gamma ray were detected by a High-purity Germanium detector clover and delayed neutrons were detected with the IDS neutron time-of-flight detector. Preliminary results showing gamma emission from neutron unbound states will be shown.   

Development of New Barrel Array Design for Transfer Reactions with Fast Beams

Single-nucleon transfer reactions allow for extraction of spectroscopic information on unstable and exotic nuclei, providing details for understanding the rapid neutron capture process (r-process). To study exotic, neutron-rich isotopes, inverse kinematics is needed with light targets and beams of heavy projectiles. Measurement of the 84Se(d,p)85Se reaction at 45MeV/u will be conducted at the NSCL in December 2017 to extract spectroscopic information on the 85Se nucleus. Single-particle transfer reactions in inverse kinematics at high energy -- such as that for the 84Se(d,p) -- are uncommon and require new designs and techniques to be developed. A modification to the current ORRUBA barrel design is needed to accommodate such changes. Features of this design include: a modular barrel able to cover a large desired angular range and detector coverage at backward angles in the lab, as well as allow for easy access to detectors without affecting the rest of the configuration. Improvements to the current design will be presented, including discussion of use in future transfer reactions with fast beams.   

Plastic Organic Scintillator Chemistry

Due to their high light output, quick decay time, affordability, durability and ability to be molded, plastic organic scintillators are increasingly becoming a more viable method of particle detection. Since the plastic is composed entirely of single molecular chains with repeating units, scintillating properties remain stable despite changes in experimental conditions. Different scintillating plastics can be modified and tailored to suit specific experiments depending on a variety of requirements such as light output, scintillating wavelength, and PMT compatibility. The synthesis chemistry of a recent but well-known scintillating polyester, polyethylene naphthalate (PEN) will be presented to demonstrate how plastic organic scintillators can be modified for different particle detection experiments. PEN has been successfully synthesized at ORNL, and procedures are currently being investigated to modify PEN using different reactants and catalysts. The goal is to achieve a transparent scintillating plastic with an incorporated wavelength shifter in the chain that scintillates with a wavelength around 440 nm. The status of this project will be presented. This research is supported by the U. S. Department of Energy Office of Science.   

Measurement of Proton-Induced Transfer Reactions with JENSA

Reaction measurements of radioactive nuclei on light targets are important to understanding the origin of and the trends in the structure of nuclei. To efficiently measure nuclear reactions, measurements require highly localized and pure light targets and need to accommodate arrays of light charged particles, gamma rays, and recoiling heavy ions. The Jet Experiments in Nuclear Structure and Astrophysics (JENSA) jet target system was designed to facilitate high resolution, low background nuclear reaction studies. To demonstrate the capability of the JENSA system, the 20Ne(p,3He)18F reaction was studied during the commissioning phase. The radioisotope 18F is one of the galactic gamma-ray sources targeted by next-generation space-based telescopes. In addition, the 20Ne(p,3He) reaction has not been previously used for the spectroscopic study of 18F. The JENSA system gives us the opportunity to study this reaction with high resolution and low background. The measurement was performed with a proton beam from the Holifield Radioactive Ion Beam Facility tandem on a neon jet of natural isotopic abundance from JENSA. The experimental setup of JENSA and preliminary results will be discussed.   

Development of New High Resolution Neutron Detector

Beta-delayed neutron emission is a prevalent form of decay for neutron-rich nuclei. This occurs when an unstable nucleus undergoes beta decay, but produces a daughter nucleus in an excited state above the neutron separation energy. The daughter nucleus then de-excites by ejecting one or more neutrons. We wish to map the states from which these nuclei decay via neutron spectroscopy using NEXT, a new high resolution neutron detector. NEXT utilizes silicon photomultipliers and 6 mm thick pulse-shape discriminating plastic scintillators, allowing for smaller and more compact modular geometries in the NEXT array. Timing measurements for the detector were performed and a resolution of 893 ps (FWHM) has been achieved so far. Aspects of the detector that were investigated and will be presented here include scintillator geometry, wrapping materials, fitting functions for the digitized signals, and electronic components coupled to the silicon photomultipliers for signal shaping.   

Testing Focal Plane Detectors for the SEparator for CApture Reactions (SECAR)

The Separator for Capture Reactions (SECAR) will be installed at NSCL/FRIB to directly measure (p,$\gamma$) and ($\alpha$,$\gamma$) reactions that are important in extreme stellar environments. Time-of-flight detectors like those implemented in SECAR are necessary to distinguish between the heavy products of the desired reactions and the unreacted beam. The time resolution and position sensitivity of a micro-channel plate (MCP) detector for the SECAR focal plane instrumentation were tested. We will present the findings of these tests as well as an alternate high energy design of a stopping detector. The new stopping detector will be characterized in further in-beam studies, and both it and the MCP detectors will be installed at NSCL/FRIB by 2022.   

Astrophysics Unearthed: Measuring the Beam-Induced 13C(d,n)14N Background in Underground Nuclear Astrophysics Experiments

Slow neutron capture or the s-process is a nucleosynthesis process that is responsible for roughly half the atomic nuclei heavier than iron. In the s-process a nucleus undergoes a series of neutron captures and the unstable isotopes beta decay to stability. The majority of neutrons for the s-process are supplied by the 13C($\alpha $,n)16O reaction, thus making the cross section one of recent interest. One complication in the study of this reaction arises from potential deuterium contamination in intense helium beams, as most analyzing magnets cannot separate the two constituents. The deuterium contamination is not negligible because at low energies (250keV and below) the cross section of 13C(d,n) is six orders of magnitude higher than that of 13C($\alpha $,n). To address this issue, a measurement of the partial 13C(d,n) cross section was performed at Oak Ridge National Laboratory's Multicharged Ion Research Facility to allow accelerator experiments to determine deuterium contamination live. The setup and preliminary results will be presented.   

Development of Signal Processing Blocks

Experiments executed on the Dubna Gas Filled Recoil Separator (DGFRS) at the Flerov Laboratory of Nuclear Reactions, Joint Institute of Nuclear Research, has proved the hypothesis of the existence of an `island of stability' of super heavy nuclei. It is a highly sensitive detection system that uses the method of ``active correlations'' which allows rare events of the decay of super heavy nuclei to be detected in almost background-free conditions. The role of the signal processing block is to distribute an event signal to the rest of the data acquisition components within the trigger system. In doing so, it will synchronize the rest of the data acquisition signal blocks when an alpha particle recoil appears in the Dubna Gas-Filled Recoil Separator detector. This helps to limit the amount of background interference as the DGFRS undergoes an experiment with a targeted heavy nucleus to receive coherent and succinct results.   

Demonstrations of a Right-Side Up Bubble Chamber Using C3F8 for Dark Matter Detection

The PICO experiment is an international collaboration that is attempting to directly detect dark matter candidates through the observation of WIMP-nucleon interactions in bubble chambers located deep underground at SNOLAB. PICO experiments have provided world-leading constraints on spin-dependent WIMP-proton interactions. At Drexel University, we have constructed a "right-side-up" bubble chamber, which places the target volume above the pressure balancing bellows, rather than below as in previous PICO detectors, that will act as both a small-scale model and as a test chamber for future PICO experiments. This new design will lead to further improvements in the constraints of WIMP-nucleon cross-sections through a higher purity target volume. With the Drexel bubble chamber, we have successfully observed a variety of event types and have begun analyzing gathered data, proving the right-side up design's viability for the next-generation bubble chambers. In the future, we will work towards completion of data analysis, and we will continue to test features for use with the bubble chambers located at SNOLAB.   

The BetaCage: Ultrasensitive Screener for Radioactive Backgrounds

Rare event searches, such as dark matter detection and neutrinoless double beta decay, require screening of materials for backgrounds such as beta emission and alpha decaying isotopes. The BetaCage is a proposed ultra-sensitive time-projection chamber to screen for alpha-emitting and low energy beta-emitting (10-200 keV) contaminants. The expected sensitivity is 0.1 beta particles $(per keV-m^2-day)$ and 0.1 alpha particles $(per m^2-day)$, where the former will be limited by Compton scattering of external photons in the screening samples and the latter is expected to be signal-limited. The prototype BetaCage under commissioning at South Dakota School of Mines & Technology is filled with P10 gas (10\% methane, 90\% argon) in place of neon and is 40 x 40 x 20 cm in size. Details on design, construction and characterization will be presented.   

Scintillator Detector Development at Central Michigan University

Experimental nuclear physics relies both on the accuracy and precision of the instruments for radiation detection used in experimental setups. At Central Michigan University we have setup a lab to work with scintillator detectors for radioactive ion beam experiments, using a Picosecond Laser and radioactive sources for testing. We have tested the resolution for prototypes of large area scintillators that could be used for fast timing measurements in the focal plane of spectrometers, such as the future High Rigidity Spectrometer at the Facility for Rare Isotope Beams (FRIB). We measured the resolution as a function of the length of the detector, and also the position of the beam along the scintillator. We have also designed a scintillating detector to veto light ion background in beta-decay experiments with the Advanced Implantation Detector Array (AIDA) at RIKEN in Japan. We tested different configurations of Silicon Photomultipliers and scintillating fiber optics to find the best detection efficiency.   

Developing a Modern Low Cost Apparatus to Measure Muon Flux vs. Angle at Muhlenberg College

Experiments using cosmic ray muons have been a staple of the undergraduate lab for decades. Muhlenberg seeks to modernize one of these experiments, and implement it inexpensively. Cognizant of the widespread use of Silicon Photomultipliers (SiPMs) in the research environment, our detector employs SiPMs instead of PMTs. Furthermore, a simulation activity has been developed to accompany the laboratory experiment. Our detector design consists of two small plastic scintillators arranged so that coincidence measurements select cosmic ray muons of particular angles with respect to the zenith. Each scintillator is attached to an SiPM and electronics to process the signal. A crude prototype was constructed last summer that produced results consistent with the well established dependence of flux on polar angle, and a simulation was created that also produced consistent results. Progress in the development of the electronics for the SiPMs, the overall design of the apparatus, and the accompanying computer simulation will be reported.   

POLARIS: Portable Liquid Argon Imaging Scintillator

Liquefied noble gas detectors have become widely used in nuclear and particle physics, in particular for detecting neutrinos and in dark matter searches. However, their potential for neutron detection in low-energy nuclear physics has not yet been realized. The University of Michigan has been constructing a hybrid scintillating time projection chamber for detection of neutrons in the 200 keV – 10 MeV range. The scintillation material is argon, and various dopants to improve detector efficiency are being explored. With collection of both scintillation light and ionization charge, improved energy resolution for neutrons is expected compared to existing measurement techniques.   

Effect of afterglow pile-up on the response function of CsI(Na) detectors

Precision measurements in nuclear spectroscopy require the characterization of detectors used for experiments. Instrumental effects from detectors and associated electronics can adversely impact measurements. A known effect in the detection of nuclear radiation is the superposition of signals from independent events which are detected within a given time window, called pile-up. Methods are available to correct measured spectra for pile-up effects when the two signals occur within a time window comparable to the duration of the signal. For some detectors based on inorganic scintillators, signals have a long-lasting and weak component called afterglow. This component lasts longer than the prompt part of the signal, so the probability for a second signal to pile up on this component is large and can affect measurements. There are no known standard methods available to correct for this effect. This presentation summarizes a study of pile-up effects with CsI(Na) scintillation detectors. It involves measurements of the energy of gamma radiation from radioactive sources as a function of counting rates. The effects on the detector's response due to afterglow pile-up is compared to a change in the detector's gain.   

Sensitivity of Reaction Rates in X-Ray Burst Models

We present a computational project on the rapid-proton capture process that occurs in accreting neutron stars. Our research involves conducting a sensitivity study of the rp-process to nuclear reaction rates in simulations using various compositions for the accreted material onto the neutron stars. In this research, we analyze the effects these variations of composition have on the resulting X-ray bursts simulated by a single-zone rp-process model. Current work is focused on modifying the initial abundances of accreted hydrogen and helium, including a range of values that correspond to the expected composition of X-ray burst sources with reliable observational data. Our objective is to determine which reaction rates have the largest effect on the modeled bursts. A second goal of the project is to implement a script to run the rp-process code in a distributed mode in a computer cluster. With this, we will be able to extend the sensitivity study to a finer grid of different chemical compositions of the accreted material. By running the sensitivity study and examining how the computational data compares with observational data, we can identify nuclear reactions that would need better experimental constraints to improve the accuracy of the rp-process model.   

Nuclear Physical Uncertainties in Modeling X-Ray Bursts

Type I x-ray bursts occur when a neutron star accretes material from the surface of another star in a compact binary star system. For certain accretion rates and material compositions, much of the nuclear material is burned in short, explosive bursts. Using a one-dimensional stellar model, Kepler, and a comprehensive nuclear reaction rate library, ReacLib, we have simulated chains of type I x-ray bursts. Unfortunately, there are large remaining uncertainties in the nuclear reaction rates involved, since many of the isotopes reacting are unstable and have not yet been studied experimentally. Some individual reactions, when varied within their estimated uncertainty, alter the light curves dramatically. This limits our ability to understand the structure of the neutron star. Previous studies have looked at the effects of individual reaction rate uncertainties. We have applied a Monte Carlo method—-simultaneously varying a set of reaction rates—-in order to probe the expected uncertainty in x-ray burst behaviour due to the total uncertainty in all nuclear reaction rates. Furthermore, we aim to discover any nonlinear effects due to the coupling between different reaction rates. Early results show clear non-linear effects.   

Simulations of the Neutron Gas in the Inner Crust of Neutron Stars

Inside neutron stars, the structures known as “nuclear pasta” are found in the crust. This pasta forms near nuclear density as nucleons arrange in spaghetti- or lasagna-like structures to minimize their energy. We run classical molecular dynamics simulations to visualize the geometry of this pasta and study the distribution of nucleons. In the simulations, we observe that the pasta is embedded in a gas of neutrons, which we call the “sauce.” In this work, we developed two methods for determining the density of neutrons in the gas, one which is accurate at low temperatures and a second which justifies an extrapolation at high temperatures. Running simulations with no Coulomb interactions, we find that the neutron density increases linearly with temperature for every proton fraction we simulated.   

Andiamo, a Graphical User Interface for Ohio University's Hauser-Feshbach Implementation

First and foremost, I am not a physicist. I am an undergraduate computer science major/Japanese minor at Ohio University. However, I am working for Zach Meisel, in the Ohio University's physics department. This is the first software development project I've ever done. My charge is/was to create a graphical program that can be used to more easily set up Hauser-Feshbach equation input files. The input files are of the format expected by the Hauser-Feshbach 2002 code developed by a handful of people at the university. I regularly attend group meetings with Zach and his other subordinates, but these are mostly used as a way for us to discuss our progress and any troubles or roadblocks we may have encountered. I was encouraged to try to come with his group to this event because it could help expose me to the scientific culture of astrophysics research. While I know very little about particles and epic space events, my poster would be an informative and (hopefully) inspiring one that could help get other undergraduates interested in doing object oriented programming. This could be more exposure for them, as I believe a lot of physics majors only learn scripting languages.   

CASPAR - Nuclear Astrophysics Underground

The CASPAR mainly focuses on Stellar Nucleosynthesis, its impact on the production of heavy elements and study the strength of stellar neutron sources that propels the s-process, $^{13}$C($\alpha$,n)$^{16}$O and $^{22}$Ne($\alpha$,n)$^{25}$Mg. Currently, implementation of a 1MV fully refurbished Van de Graaff accelerator that can provide a high intensity α beam, is being done at the Sanford Underground Research Facility (SURF). The accelerator is built among a collaboration of South Dakota School of Mines and Technology, University of Notre Dame and Colorado School of Mines. It is understood that cosmic ray neutron background radiation hampers experimental Nucleosynthesis studies, hence the need to go underground in search for a neutron free environment, to study these reactions at low energies is evident. The first beam was produced in the middle of summer 2017. The entire accelerator will be run before the end of this year. A detailed overview of goals of CASPAR will be presented.   

Neutron Star Mergers and the R process

About half of the elements of the periodic table that are present today in the Solar System were synthesized before the formation of the Sun via a rapid neutron capture process (r process). However, the astrophysical site of the r process is a longstanding problem that has captivated both experimental and theoretical astrophysicists. Up to date, two possible scenarios for the site of the r process have been suggested: the first involves the high entropy wind of core collapse supernovae, and the second corresponds to the merger of two compact stellar objects such as neutron stars. We will study the robustness of the nucleosynthesis abundance pattern between the second and third r process peaks as produced by neutron star mergers with r process-like neutron exposures. First, we will vary parameters to obtain an understanding of the astrophysical mechanisms that create the r process. Next, we will create a program to obtain the best possible parameters based on a chi-squared test. Once we have the best fits, we will test the effect of fission in the overall isotope abundance pattern distribution. Later on, we will vary the ratio of masses of the two fission fragments and study its effect on elemental abundances.   

Study of Neutrino-Induced Neutrons in Dark Matter Detectors for Supernova Burst Neutrinos

When supernova burst neutrinos (1-50 MeV) pass through the Earth, they occasionally interact with the passive shielding surrounding dark matter detectors. When the neutrinos interact, one or two roughly 2 MeV neutrons are scattered isotropically and uniformly, often leaving undetected. Occasionally, these neutrino-induced neutrons (NINs) interact with the detector and leave a background signal similar to a WIMP. The purpose of this study is to understand the effects of NINs on active dark matter detectors during a supernova burst. ~   

Orbital Electron Capture Rates in Extreme Astrophysical Environments

In an attempt to better understand EC decay rates in hot environments, we have developed a program to examine and parse all evaluated atomic and nuclear data. Taking into account the effects of ionization on accessible decay states and electron capture probabilities, half lives across the nuclear chart can be investigated without the need for theoretical estimates. Part of the ongoing project will include isolating stable isotopes that become unstable due to ionization and estimating their stability in these new environments. In addition, we hope to account for a thermal population of excited states to better simulate these environments. This should aide in the complete understanding of nuclear processes in these extreme astrophysical environments.   

Python-Based Tool for Universal Nuclear Data Extraction

Over the past 70 years, nuclear physics experiments have provided a vast wealth of experimental data on both ground and excited state properties across the nuclear chart. In many cases, searching for and parsing the relevant nuclear structure data from previous work can be tedious and difficult. Although the compilation, evaluation, and digitization of this data by multiple groups around the world over the past several decades has helped dramatically in this respect, the process of performing systematic studies using this data can still be cumbersome and limited. We are in the process of creating a python-based program to extract, sort, and manipulate nuclear and atomic data efficiently. In its current state, the program is able to extract all atomic-shell ionization energies, excited- and ground-state nuclear properties, and all beta-decay rates and ratios. As a part of this ongoing project, we plan to use this tool to examine beta-decay rates in extreme astrophysical environments.   

Rebuilding BGO detector array for neutrino physics experiments

Coherent elastic neutrino-nucleus scattering (CEvNS) has a large enough cross section that, if discovered, could open new doors in neutrino detection, such as reductions in size and cost of neutrino experiments. CEvNS is theorized to have a $N^2$ dependence (N being number of neutrons), which can be analyzed through detection by many different materials. Thus, we propose the use of BGO as a new, potential material for neutrino detection. BGO is in excess amount in TUNL facilities in the form of a Neutral Meson Spectrometer. Because the NMS has multiple BGO sheets, it is possible to trigger these sheets as individual data points to track the path of neutrinos through charged-current interaction. Additionally, because the BGO project is an untested use of material in neutrino detection, there will be specific designs of electronics, acquisition, analysis scripts that will be reusable for future use of BGO. The final BGO detector can be deployed to Oak Ridge National Laboratory for data acquisition and analysis in the Spallation Neutron Source in high neutrino flux to track paths of neutrinos through a charged current interaction and potential detection of CEvNS and comparison to other materials for dependence on $N^2$.   

Measurement of the Ir-191,193(n,2n)Ir-190,192 Reaction Cross Section Between 9.0 and 16.5 MeV

Iridium is one of the elements prioritized by Nonproliferation and Homeland Security agencies. In addition, Ir-192 is being used in various medical treatments. Improved data and corresponding evaluations of neutron-induced reactions on the iridium isotopes are required to meet the demands of several applications of societal interest. This study measured the cross section of the Ir-191,193(n, 2n)Ir-190,192 reactions at energies from 9.0 to 16.5 MeV using the activation technique. Natural Ir samples [Ir-191 37.3{\%}, Ir-193 62.7{\%}] were sandwiched between Au-197 monitor foils and irradiated with monoenergetic neutron beams at the tandem facility of the Triangle Universities Nuclear Laboratory (TUNL). Gamma rays from the irradiated samples were counted in TUNL's low background facility using high-efficient HPGe detectors. Measured cross-section data are compared to previous data and to predictions from nuclear data libraries (e.g. ENDF).