Bulletin of the American Physical Society
2021 Fall Meeting of the APS Division of Nuclear Physics
Volume 66, Number 8
Monday–Thursday, October 11–14, 2021; Virtual; Eastern Daylight Time
Session HA: Conference Experience for Undergraduates Poster Session II (5:30 - 6:45 pm) |
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Room: Poster Room West |
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HA.00001: Hybrid Calorimeter Reconstruction Tools for AI-Driven Optimization Nathan Branson The new Electron Ion Collider (EIC) will be a novel machine in the nuclear physics sector and is at the forefront of current technology. With new technology, detector research and development (R&D) becomes ever more important to ensure the machinery is reporting the best results. With artificial intelligence (AI) becoming widespread in many professional fields, AI detector optimization is a logical step for nuclear physics. This project focuses on event reconstruction of the electromagnetic calorimeter located in the electron endcap. This calorimeter will detect scattered electrons that collide with a proton and report the energy, position, and incident angle of the electron. With this data, events are graphically and visually reconstructed. Calorimeter reconstruction methods need to be finished before optimization is started in order to verify the optimized results. With the calorimeter having two different materials, methods need to be developed to analyze the area between the materials. The reconstruction tools were built using JANA2, G4E, and ROOT. These tools are needed for verifying optimization results and future reconstruction analysis of the calorimeter. A form of Bayesian Optimization will be used for detector optimization as well as transition area reconstruction. The reconstruction tools are in place for future AI optimization which will provide better results from the EIC. |
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HA.00002: Gain Studies of Small-Pore-Size MCP PMTs in High Magnetic Fields for the Electron Ion Collider Benjamin Moses At the Thomas Jefferson National Accelerator Facility (JLab), ongoing research supports the detector and accelerator design of the Electron Ion Collider (EIC). At JLab’s High-B facility, various Microchannel-Plate Photomultipliers (MCP PMT) are being studied in a variable magnetic field. An MCP PMT is a compact device, which converts light into an electrical signal, and can be used to readout the EIC Cherenkov detectors. The main EIC detector will have a 3-T central field, and it is critical to understand if MCP PMTs retain their performance at the high fields expected at the various locations of the readout of the Cherenkov detectors. As the magnetic field increases, the gain of the PMTs decreases; but it does so at a smaller rate for smaller pore-size sensors. Here, we present our studies on the gain of a 6- micrometer pore-size Photek sensor—currently the only available multi-anode MCP PMT of this small pore size. We also show results for a 10-micrometer Planacon High-Collection efficiency MCP PMT. For several orientations relative to the field, the smaller pore-size sensor can be operated even at 2 T. The larger pore-size sensor can be operated up to nearly 2 T only at standard orientation. These results suggest that each PMT could be useable in a specific application at EIC. |
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HA.00003: Geometry Optimization of an All-Silicon Tracker for the Electron-Ion Collider Andrew J Palmer The Electron-Ion Collider (EIC) is a planned facility that will probe collisions between electrons and protons/ions over a large kinematical range to study Quantum Chromodynamics. This state-of-the-art machine requires a robust tracking system to perform high-precision vertexing and momentum measurements. A pixelated semiconductor detector is one such system, and an all-silicon tracker concept with a barrel and disks to do tracking at mid-rapidity and at forward/backward rapidities respectively, has been implemented in a GEANT4-based Monte-Carlo detector simulation software, Fun4All. Simulations were carried out with 3.0 T and 1.4 T solenoidal maps. Specific areas of interest in the geometry of an all-Si detector concept are the momentum resolution of the detector in the forward region and the vertexing capabilities of the detector. This poster describes studies to optimize the detector performance. Increasing the number of disks above 5 eliminates some acceptance gaps, but at the cost of decreasing momentum resolution by about 10%. Additionally, we study the detector performance when increasing the number of detector layers close to the interaction point. Preliminary results show that the momentum resolution does not significantly change while the transverse distance of closest approach (DCA) resolution shows a potential increase in vertexing at low rapidity, especially at high particle momentum. |
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HA.00004: Binary Mergers of Neutron Star and Mirror Neutron Stars Emily Dillingham, Hung Tan, Mauricio T Hippert, Jack Setford, David R Curtin, Jacquelyn Noronha-Hostler, Nicolas Yunes A potential dark matter candidate is the twin Higgs model known as mirror matter, which is identical to the standard model but the particle masses are heavier. Recent work [1] explored the idea of mirror neutron stars based on creating a crust to core standard model equation of state and using Lattice Quantum Chromodynamics to scale the particle masses and interactions. It was found that mirror neutron stars are significantly smaller and denser than standard model neutron stars. |
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HA.00005: An investigation of the u-bar d-bar asymmetry in the proton sea through an updated Pion Cloud Model Lucas Ehinger, Mary Alberg Recent experimental investigations have found an asymmetry in the distributions of anti-up and anti-down quarks within the proton; a result which cannot be well explained through simple perturbative gluon splitting. Instead, this result is better explained by fluctuations of the proton into pion-baryon pairs. We use a Light Front formulation of the Meson Cloud Model to describe this proton-pion cloud system as an expansion of the proton into pion-baryon states. We construct splitting functions with coupling constraints and cutoffs constrained by experimental data, and model the parton momentum distributions (pdfs) of the pion and baryons in two ways. We begin by using distributions based on experimental data and evolving them to the relevant Q2 using the DGLAP equations. We also develop a statistical model of the meson-baryon pdfs and compare the experimentally derived pdfs with the statistical. We then compare our full proton momentum distributions to experimental data collected by the E866 and more recent E906 experiments, focusing specifically on the anti-down/anti-up quark ratio. |
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HA.00006: Revisiting the Vector Dominance Model in Radiative Vector-Meson Decays Roger Janusiak, Megan G Matthews The application of the vector dominance model (VDM) to the Dalitz decay ω→μ+μ- π0 underestimates the experimental spectra, especially when approaching the kinematic limit for the dimuon invariant mass. Recently, the discrepancy became more apparent as the NA60 experiment at the CERN-SPS re-measured the ω form factor with better precision. In the present work, we augment the baseline VDM by simulating the finite size of the ωρπ-vertex through a hadronic form factor, which was introduced 14 years ago in a different context. The additional momentum dependence predicted by the form factor improves the description of the NA60 data noticeably. In addition, we have improved the intermediate ρ propagator by replacing its schematic width with a microscopic model for its vacuum self-energy. This leads to a further, albeit smaller, improvement in the description of the data. As another test of the form factor, we have checked the decay width of the ρ-meson into a gamma ray and a pion, which turns out to agree with the experimental value. We briefly look at the ρ→ηγ and ω→ηγ decay widths with the same approach and used our results from these vertices to calculate the partial widths for the η→γγ and η→π+π-γ decays as well as the energy distribution for the η→π+π-γ decay. Our results thus support the use of hadronic form factors to simulate finite-size effects in hadronic interactions and improve an apparent shortcoming of the VDM. |
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HA.00007: STAR FST Module Survey Data Analysis Emily G Branson The Solenoidal Tracker at RHIC (STAR) experiment at BNL investigates proton structure and strong interactions through proton-proton, proton-nucleus, and nucleus-nucleus collisions. In order to measure events at lower angles (closer to the colliding beams), the STAR Forward Upgrade is being implemented. This upgrade includes the addition of a Forward Silicon Tracker, which can be used to track the locations and momenta of charged particles. To interpret measurements from this tracker appropriately, a detailed understanding of the physical layout is needed-- in particular, quantifying offsets between the intended and actual positions of the tracking detectors. In order to account for these offsets, alignment matrices are created by comparing the measured positions of reference points on the tracker with their ideal positions. These matrices can be applied to measurements in order to shift them from the ideal coordinates into real-world coordinates. The processes involved in constructing the alignment matrices will be presented. |
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HA.00008: Measuring η Longitudinal Double-Spin Asymmetry ALL with 2012 STAR Endcap Calorimeter Data Maggie M Bliese Using the Solenoidal Tracker at RHIC (STAR) we can measure the longitudinal double-spin asymmetry (ALL) in the production of η particles from the collisions of longitudinally polarized protons at √s = 510 GeV. The η particles decay into two photons. These photons produce electromagnetic showers in the Endcap Electromagnetic Calorimeter (EEMC) from which the energies and positions of the incoming photons are determined. From these data, we can then calculate the invariant mass of photon pairs and produce a two-photon invariant mass spectrum. In this spectrum, some pairs of photons are from η-decays and others are combinatorial background. The spectrum is then fitted using a Gaussian function to represent the η particles plus a polynomial function to describe the background photon pairs. The total number of η particles is then obtained from integrating the fitted Gaussian function. Finally, the ALL is calculated from the number of η particles produced in collisions of protons with different spin alignments, from which we can infer information about the gluon contribution to the spin of the proton. The status of the analysis using the 2012 data set will be presented. |
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HA.00009: Seeking the Magnitude of the Gluon Contribution to Proton Spin with STAR Endcap π0s Marcus Engstrom, Nicholas Gilles, Adam Gibson-Even The spin of the proton is known to be 1/2 ħ. It arises from the spin and orbital angular momenta of the proton’s constituents: quarks and gluons. The relative contributions of various components remain uncertain, with the quark spin contribution significantly lower than once anticipated. We seek to quantify the gluon spin contribution, in particular. At the RHIC-STAR experiment at Brookhaven National Laboratory (BNL), we observe collisions between spin-polarized beams of protons. In this measurement, our probe of initial-state gluons will be the neutral pion (π0), abundantly produced in such collisions. The π0s rapidly decay into two photons, which we can detect with STAR’s Endcap Electromagnetic Calorimeter (EEMC). We have been calibrating and reconstructing the 2013 data to form both photon and π0 candidates and storing this information in data structures called trees. We track the reconstruction process and assure its quality. We will describe our efforts to identify bad data using quantities including π0 mass distributions and the signal to background ratio. We will present the status of the EEMC π0 measurements using the 2013 dataset and our quality assurance analysis. |
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HA.00010: Rivet Analysis of Low-Momentum Direct Photon Yield from Au+Au Collisions Nikolas K Hunt, Christine E Nattrass, Christal A Martin, Antonio Silva At the Relativistic Heavy Ion Collider (RHIC) beams of ionized particles are collided into each other at nearly the speed of light. Due to the extremely high energy of these collisions, the particles go beyond the boundary of maintaining hadronic form, thus momentarily creating a quark gluon plasma (QGP) which can be studied. Photons are an extremely useful probe of the QGP due to their large mean free path in the medium, allowing them to travel non-interactively through the strongly dominated material. The PHENIX collaboration measured the photons and other particles produced in heavy ion collisions at multiple energies during the beam energy scan at RHIC. The Robust Independent Validation of Experimental and Theory program (RIVET) uses Monte Carlo modelling as a means of comparison to the experimental data. We used Rivet to make comparisons between low-momentum (0.4 < pT < 3 GeV/c) direct-photon yields from Au+Au collisions at various energies and several other collision systems measured by PHENIX. These yields are analyzed and plotted along with their respective comparisons to theoretical models via RIVET and the results are discussed. |
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HA.00011: Implementation of The RHIC Zero Degree Calorimeters in sPHENIX Geant4 simulation Shuhang Li
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HA.00012: Quantum Convolutional Neural Networks for Jet Classification Hector A Hernandez, Andrea Delgado Jets are an essential tool part of in nuclear and particle physics quest to in the study subatomic matter as they constitute the experimental signature of quarks and gluons. Vast amounts of data need to be processed to classify jets according to their origin. Some techniques have been devised to speed up this task while maintaining performance, when compared to traditional cut-based techniques. Some of these methods include machine learning. Quantum computing holds the promise of speeding of some of the computationally expensive tasks in physics analysis such as classification and clustering. We propose to develop a quantum algorithm based on a convolutional neural network and apply it to jet classification. |
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HA.00013: Performance Characterization Studies of The sPHENIX Outer Hadronic Calorimeter Scintillating Tiles Heleen Amedi
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HA.00014: Hadronic Calibration of Topological Clusters in the sPHENIX Experiment Nick Larson The sPHENIX experiment is designed to measure jets from heavy ion collisions. Topological calorimeter clusters, clusters of energy between all calorimeter segments, can be used as input to jets. We study the single particle performance for topological clusters. Separating clusters that are dominantly hadronic (i.e. from charged pions) compared to dominantly electromagnetic (i.e. from π0) can be used to perform hadronic energy scale calibrations. In this poster we present the performance of hadronic/electromagnetic separation of topoclusters and their use as a calibration tool. |
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HA.00015: Calculating Centrality and Geometric Quantities of High Energy Particles in Nuclear Collisions Using the Glauber Monte Carlo Model Courage Lahban In order to understand the nucleus-nucleus overlap in relativistic heavy ioncollisions, the Glauber Monte Carlo (GMC) is used to simulate the collisions be-tween the nucleons and the resulting particle production. We use this approachto explore the collective number of incident nucleons that participate in a spe-cific nuclear interaction and the shape of the overlap between these nuclei. Thisstudy used the GMC to generate a series of nuclei collisions of different impactparameters (b), where for each collision, the distribution of nucleons withinthe nuclei was determined via the Wood-Saxon distribution. The number ofbinary nucleon collision (Nbin) and the number of participants (Npart) were de-termined for each simulated collision. A particle production model, negativebinomial distribution (NBD) was incorporated with the GMC as a measure forcentrality to simulate the production of charge particles for Au + Au and O+ O (√SNN= 14.5 GeV and 200 GeV) respectively to the impact parameter.The latter was directly compared with experimental data from the SolenoidalTracker at RHIC (STAR) to determine centrality based on particle multiplicityat forward Pseudo rapidity (η).Finally, the results from this study are used to determined momentum dis-tributions for the total charged particles produced and to calculate eccentricitywhich is relevant for measuring the shape of various collisions across differentevent classes and elliptic flow of heavy ion mesons. These particles hold relevantinformation on the initial conditions of heavy ion collisions and are importantto understand the properties of the dense state of matter Quark Gluon Plasma(QGP) in Quantum Chromodynamics (QCD) |
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HA.00016: Simulating Trident Events in the NOvA Detector Nora Hoch Trident events are a rare neutrino interaction where a charged lepton and antilepton pair is generated by a neutrino interacting with a heavy nucleus. These interactions are allowed by the Standard Model but may have information about beyond the Standard Model. The NOvA experiment has been running at Fermilab since 2014 and may have recorded approximately 100 trident events out of 100 million total events. The first step in finding these events out of the larger sample is to have accurately simulated trident events in the detector to use as examples when building analyzers. In order to accurately simulate the trident events the events need to be overlaid with other neutrino interactions and they need to occur at a properly calibrated flux rate. The method we used was to take real detector events and replace them with Trident events while reweighting their frequency according to the cross section of the trident event. The reweighting was done through the rejection sampling method. The resulting simulations contained both the trident events and the original detector events to accurately represent the way that trident events would appear in the detector. These tagged events can then be used to build analyzers to identify real trident events in the NOvA data. |
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HA.00017: Source Mass Development for the Axion Resonant InterAction DetectioN Experiment (ARIADNE) Emma R Hogan, Joshua C Long The axion, a light pseudoscalar particle postulated as a solution to the strong CP problem of quantum chromodynamics, has emerged as a leading dark matter candidate. It is also predicted to mediate weak forces between fermions. The Axion Resonant InterAction DetectioN Experiment (ARIADNE) uses Nuclear Magnetic Resonance techniques to probe axion-mediated forces between nucleons with unprecedented sensitivity. A dense, non-magnetic, rotating sprocket is brought into close proximity with a cell of polarized 3He atoms, which are in turn monitored for an induced transverse magnetization with a SQUID sensor. Matching the source rotation to the frequency of the 3He precession is critical to reaching the desired sensitivity. This poster describes the techniques used to develop the source mass, including a periodic, reflective pattern on it for tracking the angular velocity with a laser. Thin film deposition is used to create metallic patterns on a silicon wafer, which is then attached to the sprocket. This process has demonstrated good pattern adhesion and conductivity. The projected sensitivity of the experiment is also discussed. |
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HA.00018: Optimizing the Design of a Cherenkov Detector for a New Two-Photon Exchange Experiment Gabriel N Grauvogel The discrepancy between polarized and unpolarized measurements of the proton’s form factor ratio may be caused by two-photon exchange (TPE), though the evidence has so far been inconclusive. Recent experiments, including OLYMPUS, extracted the TPE contribution to elastic ep scattering by measuring the e+p to e-p cross section ratio, but generally lacked the energy and precision to probe kinematics where the discrepancy is large. The TPEX Experiment, proposed to be run at DESY, aims to measure the same cross section ratio to sub-percent precision at momentum transfers exceeding 4 GeV2/c2, sufficient for a decisive test. Monitoring the relative e+ and e- luminosities will be crucial, and TPEX will employ a pair of quartz Cherenkov counters to monitor the Møller/Bhabha rates at forward angles. I will present the results of Geant4 simulation studies performed to optimize the design and placement of the counters in order to minimize the eventual systematic uncertainty. These studies show that the proposed monitor design is robust to offsets in beam and collimator alignment, the two primary systematics for the OLYMPUS experiment luminosity monitor. |
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HA.00019: Far-from-equilibrium search for the QCD critical point Isaac M Long, Travis Dore, Debora Mroczek, Jacquelyn Noronha-Hostler, Yukari Yamauchi, Claudia Ratti, Paolo Parotto Theoretical uncertainty remains about the correct description of the Quark-Gluon Plasma (QGP) near the conjectured quantum chromodynamics (QCD) critical point. As a first approach, we use a 0+1D hydrodynamic model with full shear and bulk viscosity coupled to an equation of state the contains a critical point using a 3D Ising model. Then we vary the size of the critical region, specifically looking at interesting behaviors of the speed of sound (that should diverge to zero at the critical point) that in turn affects the magnitude of the bulk viscosity. Varying then the initial conditions in terms of how far-from-equilibrium that the system begins, we are able to generate a band of potential hydrodynamic trajectories for different types of critical points to study various properties of the QGP such as the effective pressure, Knudsen and Reynolds numbers, and lifetime of the system. |
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HA.00020: Analyzing High Energy Physics data with Rivet and comparing to Monte Carlo models Adam C Tilley, Christine E Nattrass, Antonia Silva, Christal A Martin The Quark Gluon Plasma (QGP) is a phase of matter created in extremely high energy collisions of nuclei in particles accelerators such as the Large Hadron Collider (LHC) in Switzerland or the Relativistic Heavy Ion Collider (RHIC) in New York. We can compare data with Monte Carlo models using the Robust Independent Validation of Experimental and Theory program (Rivet). In particular, we often examine the production of charged particles in heavy ion collisions to gain deeper understanding of the properties of the QGP. A Rivet analysis is implemented for identified particle yields and particle ratios in gold-gold collisions and is used to make comparisons of data and PYTHIA Angantyr. |
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HA.00021: Pre-equilibrium effects on the applicability of relativistic viscous hydrodynamics Zhanghao Li, Jacquelyn Noronha-Hostler, Christopher Plumberg In order to preserve causality in relativistic viscous hydrodynamics simulations of heavy-ion collisions, it has been recently show that a pre-equilibrium free streaming stage can play a crucial role. Freestream is an open-source Python package from the Duke-QCD group which implements the pre-equilibrium free streaming process for heavy-ion collisions. Freestream provides input for hydrodynamics codes such as the energy density, relative flow velocity, shear-stress tensor, and bulk pressure. Here we couple Freestream code together with the smoothed particle hydrodynamic (SPH) code v-USPhydro in order to explore the effects of free streaming on SPH evolution. Initial simulations are shown tracking Knudsen and Reynolds numbers of individual SPH particles with and without Freestream. |
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HA.00022: Solving Relativistic Three-Body Integral Equations in the Presence of Bound States and Resonances Taylor R Powell, Andrew W Jackura, Raul A Briceno Three-body interactions play an important role throughout modern-day particle, nuclear, and hadronic physics; many experimentally observed reactions of interest for testing the Standard Model result in final states composed of three particles or more. Due to these issues, a full description of three-body interactions from Quantum Chromodynamics is required. The focus of this project was to extend previous results for a two-body subsystem with a bound state to include resonance channels. We first derived a novel single-variable observable, denoted as an intensity distribution, which is proportional to the probability density of the three-body scattering amplitude. We explored this distribution in the context of established results for a two-body subsystem with a bound state. We then implemented a purely resonant two-body Breit-Wigner scattering amplitude and examined the consequences for the three-body intensity distribution. Finally, we developed a model two-body scattering amplitude with both a resonant and a bound state and examined the three-body scattering intensity distribution for this system. For each of these two-body scattering subsystem models, intensity distributions were computed, resulting in novel graphs of relevant scattering behavior. |
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HA.00023: Critically Analyzing the Existence of the X17 Particle Orion Ning, Ben Ormond The X17 particle is a hypothetical protophobic boson proposed in 2016 by Krasznahorkay et al. at the Institute for Nuclear Research, Hungarian Academy of Sciences (ATOMKI) in order to explain excess decays in the production of e-/e+ pairs by certain nuclear transitions. While the implications of such a particle have been connected to dark matter and ‘the fifth force,’ various critiques, including the inability by others to reproduce the signal, suggest that the proposed X17 particle must be treated with some skepticism. In this work, we present and analyze simulations probing ATOMKI’s work. In particular, we simulate electron and positron events within the relevant geometry of ATOMKI’s experimental apparatus, focusing on the asymmetry of e-/e+ detector efficiency combined with various other quantities which could help to explain the X17 signal within the Standard Model. We conclude that ATOMKI’s setup manifests some discriminatory effects for e-/e+, strengthening the possibility of a Standard Model explanation for the X17 signal and prompting further investigation. |
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HA.00024: Proton-Proton Collision Analysis Using Rivet Justin Piel, Christine E Nattrass, Christal A Martian, Antonio Silva Protons along with neutrons are contained in the nucleus of every atom and are themselves composed of smaller particles called quarks bound together by gluons. Confinement means that a quark has ever been observed in isolation and quarks only observed bound together to create particles like protons and neutrons. By colliding nuclei at sufficiently high energies, we are able to create extreme enough conditions in which the nuclei can melt into each other which frees the quarks from their gluon bindings called the quark-gluon plasma. Proton-proton collisions provide an important reference for these studies. Data from these collisions can be compared to Monte Carlo (MC) event generators using a program called Robust Independent Validation of Experiment and Theory (Rivet). A Rivet analysis for proton-proton collisions at sqrts = 7 TeV has been implemented and tested using PYTHIA and JETSCAPE as MC event generators. This is the first time JETSCAPE Monte Carlo has been used with Rivet and tests JETSCAPE’s simulations of proton-proton collisions. |
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HA.00025: Physics Extraction Using Deep Learning with Uncertainty Quantification Aislinn C Whalen, Pawel Ambrozewicz, Astrid N Hiller Blin, Wally Melnitchouk, Michelle P Kuchera, Braden Kronheim, Raghu Ramanujan, Nobuo Sato, Brad Shook Deep learning methods with uncertainty quantification were evaluated for the extraction of the mass and the Breit-Wigner parameters of the rho mass distribution in the context of two pion channels in photon-production. Our simplified model takes into consideration the relativistic Briet-Wigner distribution peak as well as background noise. This provides the final step in an end-to-end deep learning framework that is being actively developed by scientists at the Theory Center at Thomas Jefferson National Accelerator Facility for analysis of data from photon-hadron collisions. Deep neural networks combined with data resampling were used to quantify uncertainty in the mass (mr) and width (Γ) predictions, and this method was compared to deep learning methods that incorporate uncertainty quantification into the training, such as approximate Bayesian Neural Networks and quantile neural networks. Results and comparisons of these methods will be presented. |
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HA.00026: Recalibrating the NJL Model to Neutron Star Observations Gema P Villegas, Andrew W Steiner Dense quark matter in neutron stars is often described by the Nambu—Jona-Lasinio (NJL) model. The NJL model parameters are often determined by ensuring that the vacuum properties of the model (e.g. the mass of the pion) match with experiments. In this work, we re-envision the NJL model as a purely phenomenological model designed to describe quark matter at high densities. We calibrate the model with neutron star observations, rather than the properties of matter in a vacuum. This allows us to explore a large range of possible descriptions of dense quark matter, while still retaining the underlying symmetries of quantum chromodynamics (QCD). We construct a Gibbs phase transition between the NJL model and a Skyrme model for the equation of state of nucleons. Additionally, we describe the set of NJL parameters that lead to neutron star mass-radius curves that match recent gravitational wave and photon-based neutron star observations. |
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HA.00027: Predicting Reduction of Plasma Instabilities Using a Neural Network Aishwarya Vijai, Diana S Parno, Ana V Hernandez, Manuel Klein The KATRIN experiment is designed to find the neutrino mass from analyzing the kinematics of tritium beta decay. Tritium beta decay produces positive ions and low energy electrons, which create a plasma. This plasma is found at the source section of the KATRIN experimental setup and it determines the starting potential of higher energy beta electrons. Variations in this plasma affect the tritium beta spectrum that is analyzed to determine the mass of the neutrino. Therefore, an optimal voltage must be applied at the rear wall in the source section to minimize instabilities in plasma potential. For this purpose, rear-wall current scans are carried out. These scans observe the current at the rear wall when the rear wall voltage changes and determine an optimal rear wall voltage at the time of the scan. I will report progress on a neural network that will utilize data from these rear-wall current scans to obtain the optimal rear wall voltage at times between scans. This will lower systematic uncertainties that arise from plasma instabilities in the KATRIN experiment. |
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HA.00028: Neutrino Flux from Beta-Decaying Isotopes at the SNS Samuel Vasquez, Rebecca L Rapp, Diana S Parno The COHERENT collaboration measures neutrinos from the Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory. SNS operations create radioactive nuclei whose beta decays contribute to this neutrino flux. With beta decays producing a flavor of neutrinos different from those from decaying pions, the neutrinos from each source are distinguishable within simulated SNS operation. In this work, isotope production data collected from SNS operation have been used to determine the nuclei most responsible for relevant radioactive decay events. We report progress on implementing these candidates into a Geant4 simulation of neutrino production from SNS pion decays, modified to support radioactive decay physics, in order to determine a higher precision measure of the total neutrino flux. |
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HA.00029: Studying the Stability of Pulse Shape Analysis in The Majorana Demonstrator Neutrinoless Double Beta Decay Experiment Jennifer L James The Majorana Demonstrator is an array of germanium detectors built to search for neutrinoless double beta decay of 76Ge. The experimental sensitivity is improved by application of pulse shape analysis (PSA) to identify and reject key backgrounds. One of these, targeting multisite gamma background event topologies, is based on the sharpness of the rising edge of the signal pulse. This project focuses on the stability of this multisite PSA, characterizing the drift of the PSA metric observed in calibration data. The impact of the stability on the signal efficiency and background rejection is studied. |
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HA.00030: Measuring the Neutrino-Nucleon Cross Section Using 8 Years of Muon Neutrino IceCube Data Natalie R Jones The cubic-kilometer IceCube Neutrino Observatory has observed neutrinos with energies up to 10 PeV. High-energy neutrinos may be absorbed by the Earth during deep inelastic scattering (DIS) with nuclei. This creates a deficit of Earth-transiting neutrinos, which can be detected by IceCube. Earth's absorption of neutrinos at high energies can therefore be used to determine the neutrino-nucleon cross section as a multiple of the Standard Model DIS cross section. The DIS cross section is subject to nuclear modifications such as shadowing, and due to differences in the proton:neutron ratio for different regions of the Earth. For this analysis, we measure the muon neutrino cross section using a Poisson maximum likelihood fit for the transmission rate of through-going neutrinos. The first muon neutrino cross section measurement using 1 year of IceCube data showed results consistent with the Standard Model. Here, we show the analysis using 8 years of data, with studies into systematic uncertainties. In particular, I will present studies of the incident neutrino flux, showing how the calculated cross section depends on assumptions about the atmospheric and astrophysical neutrino flux. |
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HA.00031: Directional Neutrino Detection with PROSPECT Manjinder Oueslati The Precision Reactor Oscillation and Spectrum Experiment (PROSPECT) detects reactor antineutrinos through inverse beta decay (IBD) at a short baseline range of 7-9m from the U-235 fission isotope core of the High Flux Isotope Reactor (HFIR). The PROSPECT detector has a segmented design of 154 optically separated segments filled with a Li-6 loaded liquid scintillator with high light yield properties that allows for precise event localization. Antineutrinos are detected through IBD by tracking the location of the reaction products, a positron, and a neutron, which undergo annihilation and delayed neutron capture on Li-6 respectively. On average the neutron retains the directional aspect of the antineutrino, which allows for a spatial displacement measurement to reconstruct the direction of the neutrino. My analysis uses data taken with the PROSPECT detector from March to October of 2018, there were 95.6 (73.1) calendar-days of reactor-on (-off) data. Data results are compared to Monte Carlo simulations. I present an analysis of the mean displacement of prompt and delayed IBD events that agrees with the known location of the HFIR reactor with respect to the PROSPECT detector. |
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HA.00032: P-Type High Purity Germanium Ring Diode Detectors for use in Neutrinoless Double Beta Decay Experiments Giovani R Leone, John F Wilkerson P-Type Enriched High Purity Germanium (HPGe) detectors are useful in rare event searches because of their excellent energy resolution. To measure rare single-site events, such as neutrinoless double beta decay, it is critical to reject multisite events while keeping the single-site events to minimize background signal in measurements. The Ring-Diode Detector (RDD) is a proposed HPGe detector geometry designed to have excellent single-site versus multi-site event discrimination abilities. The RDD electric and potential fields were simulated and the depletion voltages of various detector configurations and impurity profiles were estimated in Julia using the Solid State Detectors Packages. The effects of the electric field on charge clouds deposited within the fully biased RDD were discussed. Further analysis of the RDD's event discrimination properties, including analysis of the simulated pulse-shapes, is suggested to better ascertain its event discrimination capabilities. |
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HA.00033: Extended High Temperature Exposure of a Silicon Photomultiplier for the nEXO Neutrinoless Double Beta Decay Experiment John Blatchford, Michelle G Wellman, Reed Cohen, Jack Bolster, Thomas E Pinto Franco, Michal Tarka, Andrea Pocar The Pocar Lab located at UMass Amherst is one of many labs working with the next-Enriched Xenon Observatory (nEXO) collaboration, assisting in the pursuit of detecting neutrinoless double beta decay in Xenon-136. We report on the effects of an accidental baking of the Pocar lab's Liquid Xenon cell, subjecting a Hamamatsu VUV4 Silicon Photomultiplier (SiPM) to elevated temperatures of 460 Kelvin for a duration of approximately 2.5 days. Producing ratios of comparable SiPM signal amplitude data from before and after the event, we find an increase in the Photon Detection Efficiency (PDE) of the SiPM, ranging from 25 to 30 percent. A comparison of current-voltage (IV) curve plots in the same manner indicate little to no internal damage to the SiPM. We postulate that the PDE boost could be attributed to the high temperatures helping remove potential debris on the surface of the SiPM, citing a study done by Hamamatsu. |
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HA.00034: Nab Detector In-situ Timing Study Brandon Stone The neutron beta decay process provides us with sensitive means to probe the weak nuclear interaction for potential new physics beyond the standard model. The Nab experiment will take high precision measurements of the electron-neutrino correlation parameter, a, and the Fierz interference term, b, by precisely measuring the two observables, proton time of flight, and electron energy. The proton momentum is extracted from the proton time of flight. The systematic error budget for Nab demands the average proton time of flight should be known with an uncertainty less than 1 ns. To characterize the timing of the Nab detectors, we will perform a high precision in situ measurement of the Nab Si detectors. This entails using a NaI gamma detector and high quality digitizer as a coincidence tag for the Si detectors with radioactive sources. This will allow us to evaluate the timing systemic effects of the Nab experiment. This poster will focus on the characterization of the NaI detectors as well as the coincidence method for in situ measurements. |
Not Participating |
HA.00035: Data Analysis and Simulations for the Neutron Electric Dipole Experiment at Spallation Neutron Source (nEDM@SNS) Kimi Medina The experiment conducted at Oak Ridge National Laboratory (ORNL) using their Spallation Neutron Source (SNS) instrument aims to measure the neutron’s electric dipole moment (nEDM), if it exists, and increase the precision of these measurements by a factor of 100. SQUID (superconducting quantum interference device) magnetometers are utilized to measure the precession frequencies of Helium-3 atoms. The magnetic field causes the spins of the UCNs and Helium-3 atoms to precess, the latter of which is then detected in the SQUID detectors [1]. At the University of Kentucky and other institutions, we utilize Monte Carlo simulations that combine SQUID signals with white and pink noise scenarios to help us predict the possible environments in which the nEDM@SNS experiments occur. The same process was done using scintillation functions, whose purpose is to simulate the frequency of capture events between Helium-3 atoms and UCNs, which occur when the spins of the two particles are antiparallel. ROOT is used to analyze these simulated events through histogram fitting and other data analysis methods [2]. With these tools and methods, we aim to formulate code that can be used to gather and process data for us to interpret and analyze. This project successfully analyzed the effect of linearly and quadratically varying magnetic fields on the error estimates of UCNs’ and Helium-3 atoms’ precession frequencies, using the tools mentioned previously. |
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HA.00036: Characterization of photomultiplier tubes for heavy water detector Alejandro J Arteaga, Diana S Parno, Rebecca L Rapp The COHERENT collaboration uses the Spallation Neutron Source at Oak Ridge National Laboratory as a source of pion-decay-at-rest neutrinos. The absolute neutrino flux from this source will be measured using a planned dual-module heavy water Cherenkov detector. To determine how the photomultiplier tubes (PMTs) used in the detector will be affected by the Earth's magnetic field, data provided by the manufacturer's specification sheets was used to calculate the loss in collection efficiency due to a magnetic field with a similar magnitude. We analyzed data taken with a PMT in a light water tank. We report progress on a spectral comparison between simulated and detected cosmic ray muons and subsequent Michel electrons. |
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HA.00037: Shaping the neutron beam profile at the Nab experiment Michael K Bowler The Nab experiment, currently being installed at the Fundamental Neutron Physics Beamline at the Spallation Neutron Source at Oak Ridge National Laboratory, will make precise measurements of unpolarized neutron beta decays, in particular the electron-neutrino correlation coefficient, a, and the Fierz interference term, b. In Nab, the neutron beam passes through the decay volume, from which decay electrons and protons are guided by a long electromagnetic spectrometer to two silicon detectors. These detectors record the electron energy and proton time-of-flight. A known source of error in the determination of a is the “edge effect” caused by non-uniformity in the beam profile as it passes through the decay volume and the gyration of the decay products in the magnetic field. In order to achieve the desired level of precision for the measurement of the neutrino-electron correlation coefficient, the neutron beam must therefore be sufficiently uniform in the decay volume. I will discuss efforts to shape and understand the beam profile, including the fabrication of the internal collimation system, simulations conducted in McStas, and direct measurements of the beam profile via copper foil activation. |
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HA.00038: Cross Section of the 10B(α,n)13 N Reaction via Activation Joseph M Forchetti, Richard J deBoer, Michael C F Wiescher, August Gula, Phillip Scholz, Rebeka Kelmar, Shahina Shahina, Chevelle Boomershine First generation stars are made up lighter nuclei than later generations. The triple alpha process is what primarily converts to lighter nuclei into heavier nuclei, but there are other reaction chains that are important to the nucleosynthesis. One of these reactions is 10B(α,n)13 N, which is reported on in this work. Measurements of the cross section are made down to 450 keV alpha particle energy via activation using high energy resolution germanium gamma-ray detectors. An upturn in the S-factor, inline with data from Liu et. al. that was run using neutron detection, is also seen here suggesting there is a possible resonance at this low energy. |
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HA.00039: A Phenomenological Optical Model Potential for 12C(6Li,6Li') Darwin Quiroz, Joseph Arroyo, Umesh Garg An effective potential for the scattering of 12C(6Li, 6Li') was developed utilizing a phenomenological optical model (OM) potential. The OM potential was developed using elastic cross section data from a past experiment with a 343 MeV 6Li beam. The measurements were taken at the Research Center of Nuclear Physics. Momentum analyzing spectra underwent the standard ROOT based particle identification (PID), spectra straightening, and instrumental background subtraction processes. The phenomenological OM potentials consist of a Woods-Saxon form factor for the real and imaginary central potentials along with a Coulomb potential. The OM potential was able to reproduce the elastic cross sections with a reduced chi squared of χ2 = 233 and reproduced the angular distribution of the 4.4 MeV 21+, 7.6 MeV 01+, and the 9.6 MeV 31- states with minor caveats. An automated fitting routine was developed utilizing the nuclear interaction program ECIS, that both aided the development of this OM and can be applied towards scattering processes with heavier nuclei. |
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HA.00040: Optical Model Analysis of 58Ni(6Li,6Li') Tianyi Wang, Joseph Arroyo, Umesh Garg
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HA.00041: Examining the E_x = 7262 and 7249 keV States of Fluorine-19 with the 15N(alpha,gamma)19F Reaction Graham L O'Donnell, Dan W Bardayan, Jacob Allen, Patrick D O'Malley, Drew Blankstein, Chevelle Boomershine, Sydney Coil, Richard J deBoer, August Gula, Samuel L Henderson, Shane Moylan, Daniel Robertson, Edward J Stech Properties of important neon-19 levels affect the production of the radioisotope fluorine-18 in novae and can be constrained from studies of the mirror nucleus fluorine-19. The 15N(a,g)19F reaction has been used to study the astrophysically important but relatively unexamined region of 19F between E_x=7.0-7.3 MeV (E_a ~ 3.9-4.2 MeV). A previously known 19F state at E_x=7.262 MeV was studied and a new higher spin state was discovered near 7.249 MeV. Measured information for these states include branching ratios and resonance strengths from which the gamma decay widths can be extracted. The measurement and preliminary analysis will be presented. |
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HA.00042: Particle Swarm Optimization of High Rigidity Spectrometer Yicheng Wang, Alan M Amthor, George Sun We conduct research on two coupled ion optics systems, the High Transmission Beam Line (HTBL) and the High Rigidity Spectrometer (HRS) at the Facility for Rare Isotope Beams (FRIB). Beams from FRIB are directed into the HTBL to measure the energy and velocity and transmit them to the reaction target at the end. The products are then separated and characterized in the HRS. We simulate them using an ion optical simulation COSY INFINITY. |
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HA.00043: Simulations of a Gas Jet Target Inside SOLARIS Eboni J Collins, Kelly A Chipps, Matthew Hall There are several complications of measuring the reaction rates of unstable nuclei, such as significant backgrounds present due to beam scattering, electrons from the target, radioactive decay products, or competing reactions from beam or target impurities. Gas cells and solid targets both present difficulties such as contamination from the various isotopes of the target and degradation. The Jet Experiments in Nuclear Structure and Astrophysics (JENSA) gas jet target eliminates these difficulties by providing a high density gas jet of target nuclei within a confined region. SOLARIS is a solenoidal spectrometer system that allows for high-resolution studies of direct reactions. Simulations allow us to assess the resolution and the transport properties of the solenoid spectrometer. Python code has been developed to simulate a gas jet setup inside of SOLARIS, giving us a preview of how this setup compares to the use of traditional targets like polyethylene. Several reactions, representing examples of the kinds of measurements that may be studied with this device, have been simulated. The reaction type, nuclei involved, and magnet settings have all been varied. Through these simulations, the impact of jet hardware shadowing the particle tracks for future reaction studies will be assessed. |
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HA.00044: Utilizing a Novel Neutron Filtering Technique to Analyze Multi-Neutron Datasets Oscar O Peterson-Veatch, Nathan H Frank, Warren F Rogers, Andrea Munroe Nuclear physics research along the neutron drip line is of continuing interest. Neutron-unbound states that result in multiple neutron emission are particularly challenging to measure. In an experiment run at the National Superconducting Cyclotron Laboratory, a 101.3 MeV/u 27Ne ion beam was fired into a target of liquid deuterium. Upon collision with the target, the 27Ne beam produced various nuclides. These nuclides decay producing a charged fragment and at least one neutron. A superconducting dipole magnet guides the fragments into a suite of charged-particle detectors. 26F is formed when 1-proton is removed from a 27Ne beam, which results in 25F, 24F, or 23F through one, two, or three neutron emission. This research focuses on extracting information about multi-neutron unbound states after particle emission from unstable isotopes. Analysis of experimental data was completed by running Monte Carlo simulations set to represent various decay paths. The simulated and experimental histograms are then compared to draw conclusions about what types of decay certain isotopes undergo. This process is refined through the use of a new multi-neutron filtering method developed by collaborators. This filtering method helps to better distinguish between true multiple neutron events and neutrons that interact with the detectors more than once. A comparison of results between data and simulation will be presented. |
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HA.00045: Coherent Deuteron DVCS Analysis to Extract a Beam Spin Asymmetry Nicholas G Richardson, Angela Biselli Generalized Parton Distributions (GPDs) offer insight into the internal structure of nucleons, specifically giving an in-depth look into their individual constituents namely quarks and gluons. Deeply Virtual Compton Scattering, is one of the primary ways to access these GPDs. Due to the complex nature of the spin-1 Deuteron, there are theorized to be nine GPDs. To further learn about these GPDs we are studying coherent DVCS on the deuteron (e D → e’ D’ ??) to extract a Beam Spin Asymmetry (BSA) using Pass-1 data from Jefferson Lab’s Run Group B. This run featured a longitudinally polarized beam on an unpolarized deuteron target. In this poster we will present our preliminary analysis to select events with an electron, deuteron and photon in the final state and the selection process to identify DVCS events via strict kinematic cuts. Additionally, we will show a preliminary BSA for coherent DVCS, which is the first of its kind, giving insight into the GPDs of the deuteron. |
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HA.00046: Evaluation of Timing Scintillator Geometry Thomas Baumann, Hannah J Erington, Paul L Gueye Plastic timing scintillators are used to measure the time of flight of particles travelling between two defined locations in experiments at rare isotope facilities, such as the Facility for Rare Isotope Beams at Michigan State University. Using a Geant4 simulation that includes the tracking of optical photons generated from incident protons, the effects of the geometry of the scintillator and light guide on the time-of-flight distribution are investigated. In a first step, basic parameters such as light guide thickness and the geometry of how the scintillator is attached to the light guide are varied. The output of the simulation is analyzed regarding the light collection efficiency and the arrival time of the optical photons at the photo detector. A review of this study will be presented and discussed. |
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HA.00047: Analysis and Simulation of 36Si and 34Al Reaction Products Furman W Doty, Nathan H Frank Systems involving unbound and weakly-bound are of continuing interest. This work investigates data from one such system, from an experiment performed at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University. In particular, we have examined and simulated 36Si and 34Al Beam products, produced by collision of a 48Ca parent beam and a beryllium production target. The beams of interest then impinged on an alternating segmented target, consisting of 4 Si-PIN detectors(140 micrometers thick each) and 3 beryllium targets(199 mg/cm2 thick each). The resulting neutron-unbound excited states emit one or more neutrons, which were measured in the MoNA-LISA scintillator array; This emission left behind a charged fragment ion, such as 32Mg and 33Mg which was deflected by a superconducting sweeper magnet into charged particle detectors. The neutrons and fragments, when detected in coincidence, can be examined by invariant mass analysis to determine their properties, and using these data we can determine the neutron-unbound nuclide’s decay energy prior to neutron emission. Current status of data analysis, decay energy reconstruction, and simulation of these products will be presented. |
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HA.00048: Cluster Production in MoNA Through Charge Exchange Jeremy E Hallett, Warren F Rogers, Andrea Munroe The Modular Neutron Array (MoNA) is a neutron detector composed of 144 plastic scintillator bars with 10 x 10 x 200 cm dimensions. One neutron scattering possibility in MoNA is the np charge exchange interaction where an incoming neutron swaps identities with a H proton, producing a high energy proton. These protons create additional light in adjacent bars, producing hit-clusters in the data set. A filter is currently in use that reduces the single-neutron scattering background, based on identifying and reducing these proton-induced clusters, and then checking the causal relationship of all remaining hits in an event. When a gap between detectors is introduced into the array, protons traveling across the gap can be identified by a distinct band in a plot of energy deposited vs. velocity. This event can then be used as a multi-neutron filter by vetoing events with scattering angles at 90 degrees relative to the proton's trajectory (where the scattered neutron would be detected) and then looking for additional hits across the gap which are likely separate neutrons. In our 2019 experiment investigating neutron scattering at Los Alamos National Laboratory, we clearly identified these charge exchange protons, and are using those observations to help design the future MoNA array. |
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HA.00049: Behavior of Dark Scattered Neutrons in Plastic Scintillators Ari Maki, olivia guarinello, Anthony N Kuchera The Modular Neutron Array (MoNA) is used in experiments of nuclei approaching the neutron drip line. These experiments often rely on simulations for the interpretation of their results. The purpose of this experiment is testing the accuracy of these simulations, especially dark scattering: A phenomenon where a neutron scatters off a hydrogen or carbon atom, but does not produce enough light to be detected. This experiment was run by the MoNA collaboration at the Weapons Neutron Research facility at the Los Alamos Neutron Science Center; the setup consisted of 16 MoNA detectors. One detector was placed directly in front of the neutron beam as a target. The other 15 detectors were arranged in a staircase downstream of the target to detect neutrons scattered from the target. The main sources of background in this experiment consist of cosmic muons, and neutrons which exit the collimator at an angle, avoiding the target detector but still hit the staircase. These sources of background do not exist in simulation, so it is necessary to remove them from the data. This background is indistinguishable from dark scattering, so creative methods are required to eliminate it. These methods of background removal and preliminary scattering results will be presented. |
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HA.00050: A Multi-Layered Approach to Multi-Neutron Filtering Andrea Munroe, Jeremy E Hallett, Warren F Rogers MoNA (the Modular Neutron Array) is an array of 144 plastic scintillator detectors used to detect neutrons from the decay of neutron-unbound nuclei. As MoNA will soon be used at higher FRIB energies to investigate unbound nuclei that decay by two or more neutrons, it is important to accurately identify which hits in MoNA correspond to independent neutrons. We have developed a multi-layered approach for sorting out hit clusters (produced by np charge exchange protons creating additional light in adjacent bars) and causal events (occurring close enough in spacetime to be connected by a single scattered neutron) to properly assess the independent neutron multiplicity; for 2n data sets, our goal is to enhance the true 2 neutron signal and reduce the 1n signal to below 5%. We have used our filtering algorithm to produce Edecay plots from existing experimental data sets, and have seen higher 2n statistics and increased resolution, relative to traditional causality filters. Development of our sorting algorithm continues as we search for and identify additional sorting parameters that can also be used to recover 2n events which appear causally connected (and are therefore filtered out with the current algorithm), in order to provide higher 2 neutron statistics. |
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HA.00051: External-beam development and PFAS measurements with the UML Van de Graaff accelerator Andrew Douglas, Peter C Bender, Andrew M Rogers, Yiyi Zhu
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HA.00052: Decay data of 140La for nuclear forensics Jenna N Ocheltree, Libby McCutchan, Andrea Mattera, Shaofei Zhu, Marian Jandel, Peter C Bender Complete characterization of 235U fission and the decay of its fission fragments is important to develop a database for nuclear forensics applications. In pursuit of this goal, β- decay has been characterized for 140La. 140La has significance in nuclear forensics for dating nuclear events when its relative abundance to the parent 140Ba is taken. Gamma spectra were collected with Gammasphere, currently located at ANL. The 140La sample measured was created through neutron capture at the UMass Lowell reactor. Using calibrated spectra from140La, previously observed levels have been confirmed and intensities measured, and new levels and transitions proposed are supported by coincidence spectroscopy. Preliminary results on the revised decay scheme and precision intensities will be presented. |
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HA.00053: γ-ray Reconstruction Using Neural Networks Matthew Berko Measuring γ-rays from nuclear decay is important for distinguishing different models describing the photon strength function. Because γ-rays often scatter from one detector into another within an array, one must reconstruct the actual energy of the initial γ-ray from the energies deposited in multiple detectors. Current γ-ray emission data is reconstructed using modern day addback-clustering algorithms, however due to scattering and cross-talk in detectors, the algorithms can only reconstruct a fraction of the events accurately. This research investigates the potential use of neural networks to reconstruct gamma energy and multiplicity using simulated detector data originating from DICEBOX. These results are then compared to the performance of the current clustering algorithms. If the neural network outperforms the clustering algorithms and is able to identify previously unknown patterns in the data, then it may replace the clustering algorithms to reconstruct γ-ray emissions. Excited states of 58Fe made in DICEBOX in conjunction with GEANT4 to create simulated events were used to train and test various different networks. |
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HA.00054: Using γγ-coincidence spectroscopy to detect natural radiation in soils near the Mississippi River Pranjal Singh, Anthony N Kuchera, Benjamin Crider Naturally radioactive nuclides, present in soils, contain background radiation that humans are exposed to everyday. Previous research suggests that there are some High Background Radiation Areas (HBRA), caused by climate, geography, wind and water currents that accumulate a higher concentration of these radionuclides. An investigation of one of these HBRA, Nile Delta, confirms the presence of minerals rich in U and Th from Monazite minerals, concluding that some locations have higher concentrations of radionuclides than accepted internationally.[1] One of the similarities between the Nile and the Mississippi River Delta includes that they are both undergoing erosion. The present work is a search for monazite in the Great River Road State Park, near the Mississippi River. The samples were measured with a low-background NaI(Tl) spectrometer and digital data acquisition system. Using γγ-coincidence spectroscopy to reduce background, we were able to apply coincidence gates of known gamma-ray energies originating from 238U and 232Th decay chains to identify the presence of the radionuclides in the soil samples. We were able to confirm that there is an accumulation of minerals containing 238U and 232Th near the river. |
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HA.00055: A novel mathematical technique for radioactive decay computations in supernovae simulation Thomas Lemoine Supernovae are the explosive deaths of stars with energies that allow the creation of heavy elements. They are important end-points of stellar evolution, and the elements synthesized in the explosion are crucial for the formation of earth-like planets and ultimately life as we know it. The decay of nickel and cobalt, which are synthesized in supernovae explosions, generate high-energy photons which are reprocessed into optical wavelengths by the supernova’s ejecta. Simulating these decay processes calculate the energy available for deposition into the material of the ejecta. The linear ODEs describing such decays are traditionally solved using an iterative process. In this presentation, I will describe a novel technique, using linear algebra and consisting of a coordinate transformation to uncouple these ODEs, used by the python package radioactivedecay. I extended the use of this technique in radioactivedecay to stable nuclides, which themselves scatter photons in the ejecta of supernovae. These calculations will be used as a means to calculate the abundances of fundamental isotopes such as nickel, cobalt, and iron in the open-source supernova simulation program TARDIS, and will allow for fast and accurate decay calculations to be performed at the TARDIS simulation’s runtime. |
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HA.00056: Investigating the Radiopurity of Lithium Molybdate for Rare Event Searches Jay-U Chung, Thomas O'Donnell High radiopurity materials are essential for rare event searches such as dark matter and neutrinoless double beta decay. Gamma ray spectroscopy with high purity germanium detectors is one of the most important ways to screen materials for radiopurity. In this poster, we describe a high-purity germanium detector setup in above-ground lab and report on the sensitivity to contamination of interest as 40K, 238U, and 232Th. We will further report on the radiopurity of an off-the-shelf sample of Lithium Molybdate measured with this setup. This material is potentially of interest for neutrinoless double beta decay searches as CUPID and AMORE. |
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HA.00057: Deuteron stripping reaction on 10B and 11B nuclei Samuel Anderson, Anthony N Kuchera, Duncan Snider This research project was motivated by the predicted existence of a strong resonance in 11B at 11.425 MeV. The hypothetical existence of this resonance has been considered a solution to the large discrepancy between the measured and calculated branching ratio for the phenomenon of beta-delayed proton emission in the neutron-rich nucleus 11Be. FSU’s John Fox Accelerator Laboratory was used to conduct an experiment to search for the resonance, utilizing a deuteron stripping reaction on 10B and 11B targets. A split-pole spectrograph was used to observe excited states in 10B(d,p)11B and 11B(d,p)12B. A focal plane detector was used to measure the positions of proton ejectiles from the reaction at scattering angles from 10 to 50 degrees at five-degree increments. Through the use of the data analysis framework ROOT and the calibration software SPANC, relevant peaks were identified and paired with previously recorded excited states in 11B and 12B. Angular distributions were constructed for these states. Preliminary results will be presented. |
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HA.00058: Coincidence timing and Compton suppression techniques for nuclear structure studies using the La Crosse fIREBAll Peter J Guerra, Michael Ryan, Kevin Lee, Wanpeng Tan, SHELLY R LESHER, Ani Aprahamian Throughout the history of nuclear experimentation, more precise detection methods have been theorized and accomplished to further understand the foundations of nuclear structure. We explored the viability of various scintillation detectors for potential use in coincidence with the La Crosse fInternal conveRsion Electron Ball Array (fIREBAll). One of the objectives of fIREBAll is to search for E0 transitions and to measure conversion coefficients from E2 transitions with large E0 components between J-J transitions in nuclei with multiple 0+ states. We assessed the capability of Bismuth Germanate (BGO) detectors to suppress the Compton scattering of a Germanium (HPGe) detector. Using a ROOT script incorporating data from both detectors, we greatly reduced background caused by Compton scattering. In addition, we tested two groups of Barium Fluoride (BaF2) detectors, incorporating a pulse-shape discrimination technique to remove self-activities and to determine timing and energy resolution properties. We also tested a group of Cerium Bromide (CeBr3) detectors, which exhibited exemplary fast timing and energy resolution properties. |
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HA.00059: Cross section measurements of 92Mo(p, γ) 93Tc and 94Mo(p, γ) 95Tc Jane O'Reilly, Anna Simon, Rebeka Kelmar, Chevelle Boomershine, Alexander C Dombos, Jessica Koros, Orlando J Olivas-Gomez, August Gula, Miriam Matney, Khachatur Manukyan, John P McDonaugh, Daniel Robertson, Shahina Shahina, Edward J Stech The current network calculations from a Type II Supernovae of 25M๏ model of p-nuclei greatly underproduce 92Mo and 94Mo. This discrepancy between the network calculations and solar abundances may stem from uncertainty in the astrophysical environment or the nuclear physics input, and this work examines the nuclear uncertainty. In order to experimentally examine these two nuclei, the reactions of 92Mo(p, γ) 93Tc and 94Mo(p, γ) 95Tc were measured. The High EffiCiency TOtal Absorption SpectrometeR (HECTOR), a γ-summing detector, was used with the 5U accelerator at the University of Notre Dame to measure the cross sections of these two reactions within their Gamow Windows. In this presentation, 94Mo(p, γ) 95Tc capture reaction cross sections in the energy range Elab = 1.4 − 4.4MeV are discussed. The results of this work are compared to measurements reported in the literature and those calculated using Talys 1.9. |
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HA.00060: Performance Characteristics Study for the sPHENIX Inner Hadronic Calorimeter Scintillating Tiles Jingyu Zhang The Quark Gluon Plasma (QGP) is a hot, dense soup of quarks and gluons that existed a few millionths of a second after the Big Bang. To better understand the properties of the QGP, sPHENIX, a new experiment at Relativistic Heavy Ion Collider (RHIC) will perform high precision measurements of jets in nuclear collisions. Critical to this goal is the hadronic calorimetry (HCal) subsystem, which consists of an outer and inner segment. The Inner HCal is composed of plastic scintillating tiles sandwiched between aluminum absorber plates. The Inner HCal tile testing at Georgia State University allows tiles to be sorted and aggregated into sets of five, known as towers. The tiles within a tower will have a similar light yield to optimize the calorimeter's performance. To achieve this, each tile's performance is evaluated by measuring the tile's response to cosmic rays. The distribution of tile performance helps us track the performance characteristics and calibrate the Inner HCal tiles. This poster will present the current status of the Inner HCal tile testing and assembly. |
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