Bulletin of the American Physical Society
2019 Fall Meeting of the APS Division of Nuclear Physics
Volume 64, Number 12
Monday–Thursday, October 14–17, 2019; Crystal City, Virginia
Session HA: Conference Experience for Undergraduates Poster Session (4:00pm - 6:00pm) |
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Chair: Shelly Lesher, University of Wisconsin, La Crosse Room: Salon 4 |
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HA.00001: Optimizing Performance of a Charge-Sensitive Amplifier for the LEGEND-200 Experiment Gannon Lawley The observation of neutrinoless double-beta decay would provide evidence for the proposition that neutrinos are their own antiparticle, a property that is not prescribed in the Standard Model. The proposed Large Enriched Germanium Experiment for Neutrinoless double beta Decay (LEGEND) will search for this decay mode in $^{76}$Ge by deploying high-purity germanium (HPGe) detectors enriched in this isotope. The signal from two hundred kilograms of HPGe detectors will be fed to low-radioactivity, charge-sensing amplifiers (CSA) deployed in the first phase of the LEGEND experiment: LEGEND-200. We optimized the performance of the CSA in different test conditions by varying the operating parameters (including voltages supplied to the active components of the CSA) and measured the properties of the amplified waveform, such as rise time, dynamic range, and electronic noise. The optimized parameters lead to waveforms with the following characteristics: 90 ns rise time, a dynamic range from 0 - 10 MeV, and noise of 620 keV (FWHM) at a total power consumption of 156 mW in liquid nitrogen. The optimization process will continue as the circuit is integrated with other components of the experiment. [Preview Abstract] |
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HA.00002: Selected Configuration Interaction using Reinforcement Learning Lihao Yan, Li Zhou, Chao Yang, Mark A. Caprio Configuration interaction (CI) is a widely used method for solving quantum many-body problems. The challenge of CI is to solve a large sparse eigenvalue problem. The dimension of the eigenvalue problem grows rapidly as the number of particles and the size of the Slater determinant basis increases. For many problems, the low-lying and ground state eigenfunctions exhibit localization, i.e., most of the CI coefficients are negligibly small. One approach, often referred to as the selected CI method, selects many-body basis functions, i.e., Slater determinants, that have large coefficients to construct a finite dimensional accurate approximation of the many-body Hamiltonian. However, we can only select a small subset of the important basis functions using physical intuition. Typical selected CI algorithms use perturbation theory, but they are not globally optimal. In this work, we use a reinforcement learning (RL) strategy to refine the algorithm. Each state of the RL algorithm corresponds to a particular set of many-body basis. Each action removes some basis and adds new basis into that set. A better set of basis functions is obtained after multiple training episodes. We test the performance of our algorithm against several other selected CI algorithms. [Preview Abstract] |
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HA.00003: Measurement of Optical Properties of Tetraphenyl Butadiene Samuel Naugle, Gabriel D. Orebi Gann, Michinari Sakai, Scott Kravitz, Dan McKinsey, Ryan Smith Liquid argon is a popular detection medium for both neutrino and dark matter experiments, due to the high light yield and potential for high-precision pulse shape discrimination. A wavelength shifter, such as tetraphenyl butadiene (TPB), is required in order to detect the extreme UV photons produced in particle interactions. This poster presents updates on ongoing work to characterize the microphysical optical properties of TPB. By shining UV light on thin-film TPB samples of varying thickness, both in vacuum and submerged in liquid argon, and then looking at the angular reemission distribution using a PMT, we can measure properties of the TPB, such as UV absorption length and photon reemission quantum efficiency. We have constructed a detailed, high-precision Monte Carlo model of our apparatus. A mirror is used to calibrate the Monte Carlo simulation, as well as discern to which systematic effects our experiment is most sensitive. By comparing the Monte Carlo simulation with data, this study will yield refined measurements of the microphysical properties of TPB, allowing for more control and confidence in any model of this material for next-generation detector design. This poster will present the most recent results from this work, including model predictions and vacuum data. [Preview Abstract] |
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HA.00004: Understanding quantum phase behavior through gamma-ray spectroscopy of 154Gd Zoe Rechav, E. A. McCutchan, S. Zhu, C. J. Lister, J. P. Greene, M. P. Carpenter, R. V. F. Janssens, T. L. Khoo, T. Lauritsen, D. Seweyniak Nuclei that undergo rapid transitions from spherical to deformed states can be modeled using quantum phase transitions. At N$=90$, discontinuous binding-energies indicate the simultaneous existence of spherical and deformed structures. To expand upon our knowledge of quantum phase transitional behavior at N$=90$, the decay of $^{154}$Eu to $^{154}$Gd was studied with the Gammasphere array at Argonne National Laboratory. The ultra high statistics data set allowed for precise determination of transition intensities between low-lying states in $^{154}$Gd important for interpretation of its structure. The new intensities will be used to re-evaluate the efficiency of various theoretical models to describe the phase and shape transition of $^{154}$Gd. This work was supported by the DOE Office of Nuclear Physics under contract DE-AC02-06CH11357 and DE-AC02-98CH10946. [Preview Abstract] |
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HA.00005: $^{19}F(d,p)^{20}F$ measurements using the Super-Enge Split-Pole Spectrograph with implications to Type-I X-ray bursts Alex Conley, Raffy Traas, Shelly Lesher, Gordon McCain, Ken Hanselman, Lagy Baby, Paul Cottle, Chris Esparza, Kirby Kemper, Anthony Kuchera, Gray Selby, Jessica Nebel-Crosson, Lew Riley, Ingo Wiedenhoever Accreting neutron binary systems generate frequent x-ray bursts upon breaking out from the hot Carbon-Nitrogen-Oxygen (CNO) cycle to the rapid proton-capture process (rp) by the $^{15}O(\alpha,\gamma)^{19}Ne(p,\gamma)^{20}Na$ reaction chain. Previous studies investigated the $^{19}Ne(p,\gamma)^{20}Na$ reaction rate by using the $^{19}Ne(d,n)^{20}Na$ mirror reaction, relying on experimental data from the isospin-mirror reaction $^{19}F(d,p)^{20}F$ and shell model calculations to determine which states will populate with significant cross sections. We investigate the $^{19}F(d,p)^{20}F$ reaction as an indirect study of the $^{19}Ne(d,n)^{20}Na$ to obtain reliable data and lessen existing uncertainty of the thermal reaction rate. The experiment was performed using the Super-Enge Split-Pole Spectrograph at FSU’s John D. Fox Accelerator Laboratory to measure high-resolution spectra of high-lying states in $^{20}F$. Absolute cross sections and spectroscopic factors are determined for proton resonances in $^{20}F$ at 0.66, 2.04, 2.19, 2.97, 3.49, and 3.53 MeV energies which contribute to the level structure of $^{20}F$. [Preview Abstract] |
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HA.00006: Single-Neutron Transfer to 50Ti J. M. Nebel-Crosson, L. Riley, L. T. Baby, P. Cottle, J. C. Esparza, K. Hanselman, K. Kemper, G. McCann, I. Wiedenhoever, A. Conley, S. Lesher, R. Traas, A. Kuchera, G. Selby Single-neutron states of $^{51}$Ti have been studied using the reaction $^{50}$Ti$(d,p)^{51}$Ti with a deuteron energy of 16 MeV at the John D. Fox Laboratory at Florida State University using the Super-Enge Split-Pole Spectrograph. Proton momentum spectra were measured at a scattering angle range of 10-50 degrees at five degree increments. This work is motivated by discrepancies between recent inelastic proton-scattering measurements of collective octupole states of neutron-rich calcium and titanium isotopes and Random Phase Approximation predictions, which depend on empirically-determined single-neutron structure beyond $^{48}$Ca. Preliminary results and plans of future analysis will be discussed. [Preview Abstract] |
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HA.00007: $^{10}B(d,p)^{11}B$ and $^{25}Mg(d,p)^{26}Mg$ measurements using the Super-Enge Split-Pole Spectrograph Gray Selby, Anthony Kuchera, Gordon McCann, Ken Hanselman, Lagy Baby, Paul Cottle, Chris Esparza, Kirby Kemper, Alex Conley, Raffy Traas, Shelly Lesher, Jessica Nebel-Crosson, Lew Riley, Ingo Wiedenhoever Two experiments were preformed using the Super-Enge Split-Pole Spectrograph at Florida State University’s John D. Fox Accelerator Laboratory to measure high-resolution spectra of states in $^{26}Mg$ and $^{11}B$ through the use of (d,p) single-particle transfer reactions. Spin assignment confirmation of five states above the proton threshold of $^{26}Si$ are necessary for assessing the astrophysical impact of the $^{25}Al(p,\gamma)$ reaction rate on the $^{26}Al$ cosmic abundance. We investigate $^{25}Mg(d,p)^{26}Mg$ as a mirror to $^{26}Al$ to assign spin to the mirrors to the states of interest. A previous study observed beta-delayed proton emission in the neutron-rich nucleus $^{11}Be$ with an unexpectedly high decay mode strength that can only be understood if the decay proceeds through a new single-particle resonance in $^{11}B$ strongly fed by beta-decay. A recent pre-print corroborates the study, providing the expected excitation energy. While the resonance in $^{11}B$ was not found, spin assignments of $^{11}B$ states were assigned, one of which was previously unassigned. [Preview Abstract] |
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HA.00008: Calculation and Normalization of Selected 26Mg (alpha, n) Cross Sections Kristin Ringhand, Cecilia Fasano, Meiko Volknandt, Benjamin Brueckner, Rene Reifarth, Michael Wiescher An evaporated $^{26}$Mg target on tantalum backing was exposed to $\alpha$-particle beam using the 2-MeV Van de Graaff accelerator at Goethe University Frankfurt, and the $^{26}$Mg ($\alpha$, n) cross section calculated for five beam energies between 1830 and 2000 keV. The use of a $^{3}$He spectrometer at zero degrees relative to the target allowed separation of neutrons in the region of interest from thermal neutrons. Cross sections were normalized with respect to $^{11}$B($\alpha$, n) cross sections for the corresponding energies, which were also measured using the 2-MeV Van de Graaff. While both targets showed evidence of deterioration throughout the process, this was more obviously evident for the $^{26}$Mg target. As this measurement follows prior target development and characterization, investigating appropriate target backings and thicknesses for this measurement, the significant deterioration observed provides additional information about $^{26}$Mg target stability under beam. When considered in combination with complications when using thinner targets, these observations suggest a need for thick targets and further characterization of target deterioration in order to increase the accuracy of further cross section measurements. [Preview Abstract] |
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HA.00009: 26Mg(alpha,n) and Br(n,gamma) Cross Section Measurements Cecilia Fasano, Kristin Ringhand, Meiko Volknandt, Benjamin Brueckner, Rene Reifarth, Michael Wiescher The cross sections of two different reactions were measured using the 2.5 MeV Van de Graaff accelerator at Goethe University, Frankfurt to parameterize varying stellar processes associated with understanding the origin of elements in the universe. $^{26}$Mg ($\alpha$,n) was measured using a proton beam over a beam energy range of 1.8-2.0MeV. A $^{3}$He spectrometer counted neutrons between the thermal region and reaction region from which yields and cross sections were calculated. Cross sections from this reaction will provide a constraint on neutron flux in stellar environments. To provide a constraint on stellar processes which occur in environments with lower neutron density, Br(n,$\gamma$) activation and decay rates were similarly investigated. The number of activated nuclei as a function of energy was determined using gamma spectroscopy and germanium detectors. Ten minute activations of natural bromine led to cross section measurements of Bromine isomers with most focus on $^{82}$Br which has a half life of minutes and requires sensitive detectors to measure. A more rigorous understanding of this cross section will help constrain the stellar s-process especially in our own sun. Together these two reactions provide better context for current astrophysical models and theories. [Preview Abstract] |
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HA.00010: \begin{center} Half-life measurements of isotopes relevant to the astrophysical $p$-process carried out via photoactivation at the Madison Accelerator Laboratory (MAL) \end{center} Tyler Hain, Adriana Banu One of the projects underway at MAL is related to measurement of photodisintegration reaction rates for the nucleosynthesis of the $p$-nuclei. Due to the low isotopic abundances of the $p$-nuclei, the half-lives of isotopes with fewer neutrons than the $p$-nuclei tend to be measured with large uncertainties. Our goal was to improve the uncertainty on existing data for the half-lives of $^{\mathrm{73}}$Se, $^{\mathrm{69}}$Ge, $^{\mathrm{83}}$Sr, and $^{\mathrm{63}}$Zn. These isotopes were produced at MAL via photoactivation, $\gamma $-spectroscopy was used to measure the activity of the samples over time and determine the half-life of each isotope using three data analysis methods. To confirm that they gave accurate results, we first tested these methods on a well-known isotope; an isomer of indium ($^{\mathrm{116m1}}$In) with a half-life of 54.29(17) min. A weighted mean of 8 separate measurements yielded a measured half-life for $^{\mathrm{116m1}}$In of 54.35(02) min, which agrees with the accepted value and is more precise. The final results and uncertainties obtained for the half-lives of $^{\mathrm{73}}$Se, $^{\mathrm{69}}$Ge, $^{\mathrm{83}}$Sr, and $^{\mathrm{63}}$Zn will be presented by comparing the three data analysis methods that were applied. [Preview Abstract] |
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HA.00011: Temperature Dependence Measurement of the Light Yield in Stilbene Isaiah Cox, Zhaowen Tang, Melissa Boswell, Steven Clayton, John Goett, Elena Guardincerri, Nguyen Phan, Jason Lashley, Takeyasu Ito Dark matter particle masses have been well constrained in the $>$ 10 GeV/c$^2$ range due to current direct detection efforts. To probe lower masses, it is necessary to use low Z elements in detectors, which produce higher nuclear recoil energies. We plan to explore the possibility of using hydrocarbon crystals as material for scintillation/phonon detection. Here, we present the temperature dependence of light yield for a stilbene crystal (C$_{14}$H$_{12}$ ) down to 4 Kelvin which will help determine the energy threshold for photon detection. [Preview Abstract] |
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HA.00012: \textbf{Development of the Position Sensitive Scintillator Detector (PSSD) for ANASEN } P. Hedlesky, S. Marley, J. Blackmon, C. Deibel, A. Hood, R. Malecek, A. Ryan, G. Guzik, M. Nauman, B. Ellison The Array for Nuclear Astrophysics and Structure with Exotic Nuclei (ANASEN) will be used to study reactions that are important to the formation of elements using beams of radioactive nuclei at the Tri-University Meson Facility (TRIUMF). This program will focus on the cosmological lithium problem and X-ray burst nucleosynthesis. We will describe the development of an upgrade to ANASEN and testing at Louisiana State University. The detector system uses two different types of detectors to measure reaction products and reconstruct the excitation function. Two rings of silicon detectors will measure the trajectory and energy of the reaction products. The Position Sensitive Scintillator Detector (PSSD) is being developed to measure the x-y position and intensity of the radioactive ion beam. The PSSD uses an array of 4x4 silicon photomultipliers (SIPM's) to accomplish these measurements. Preliminary results from testing will be presented and performance of the PSSD discussed. [Preview Abstract] |
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HA.00013: New Insights into Backbending from the Symmetry-adapted Shell Model Nick Heller, Grigor Sargsyan, Kristina Launey We provide new insights into the backbending phenomenon from first principles and intrinsic deformation. Backbending refers to an abrupt increase of moment of inertia at high spins along the yrast band, as observed from the nuclear spectroscopy. Here, we use the ab initio symmetry-adapted no core shell model (SA-NCSM) [1] with chiral potentials, now applicable to heavy nuclei in its valence-shell version, to investigate backbending and moment of inertia from a microscopic perspective. For two traditional examples, $^{20}$Ne and $^{48}$Cr, the microscopic calculations confirm the important role of spin alignment and configuration mixing, but surprisingly unveil no anomalous increase in moment of inertia. Furthermore, for $^{48}$Cr, we are able to reconcile contradictions between earlier mean-field and SU(3) shell models [2] – while we confirm a spherical high-spin nucleus, we find a close interplay of prolate and oblate deformed configurations with an overall spherical shape. The outcome opens the path toward further understanding heavier nuclei systems, their rotations and moments of inertia. [1] K. D. Launey, et al., PPNP 89, 101 (2016). [2] R. A. Herrera and C. W. Johnson, PRC 95, 024303 (2017). [Preview Abstract] |
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HA.00014: Characterizing gravitational wave signals from core-collapse supernovae Noah Wolfe, Sanjana Curtis, Somdutta Ghosh, Kevin Ebinger, Carla Frohlich Core-collapse supernovae (CCSNe) are the explosive deaths of massive stars, and multi-messenger events which produce signals including gravitational waves, neutrinos, isotope abundances, and light in a multitude of wavelengths. With the next-generation of gravitational wave telescopes (Advanced LIGO/VIRGO), it may soon become possible to detect gravitational waves originating from CCSNe. Here, we compute the gravitational wave eigenfrequencies for a set of CCSNe models based on the PUSH method. The models span a range of progenitor zero-age main sequence masses and two different nuclear equations of state (DD2 and SFHo). We will discuss the influence of the progenitor properties and the equation of state on the gravitational wave signal. [Preview Abstract] |
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HA.00015: Predicting Cosmogenically Activated Isotopes in Ge-76 Detectors in the MAJORANA DEMONSTRATOR Neutrinoless Double-Beta Decay Experiment Riley Ferguson The Majorana Demonstrator is an array of point-contact Ge detectors fabricated from Ge isotopically enriched in 76Ge to search for neutrinoless double beta decay, an as yet unobserved form of nuclear decay requiring neutrinos to be Majorana particles (their own antiparticles). Extending half-life limits beyond those already demonstrated requires careful control of radioactive contaminants that contribute backgrounds to 0v$\beta \beta $ searches. Cosmogenic activation of germanium, the production of radioisotopes through exposure to cosmic-rays, is a potential source of background in the Demonstrator, and for this reason efforts were taken to limit the exposure of germanium material and detectors (through shielding and underground storage) to cosmic rays throughout the construction process. Exposure was tracked throughout this process and recorded in a database; we have developed a database parser and activation calculation toolkit based in python, and are using it to calculate expected levels of cosmogenic activation based on these database records. An overview of the software suite, our calculations of expected activation rates, and preliminary background estimates will be presented. Impacts for the next-generation LEGEND experiment will also be considered. [Preview Abstract] |
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HA.00016: 2-Proton Decay from Exotic Nuclei Mira Ghazali A recent experiment at the National Superconducting Cyclotron Laboratory measured the two-proton decay of $^{\mathrm{30}}$Ar in order to better understand this decay mode into the \textit{sd}-shell. The experiment couples the S800 spectrograph to a small silicon-cesium iodide (Si-CsI) array, along with a 2D scintillating fiber array. The Si detector is used to determine the angle of the two protons, and combining the Si and CsI allows one to distinguish between different charged particles and measure their total energy. The fiber array records the angle of the heavy residue emitted from the decay. The S800 spectrograph measures the total energy and identifies the $^{\mathrm{28}}$S decay residue. A proper energy calibration is needed to accurately analyze data from the experiment. Each detector (along with the fiber array) in the experimental setup requires its own calibration. The ancillary detectors, which include the Si and CsI detectors, call for a linear calibration; this is unlike the S800 spectrograph, which is composed of several different detection systems and consist of different techniques of calibration. [Preview Abstract] |
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HA.00017: Effects of columnar recombination using a gas-ionization chamber for heavy, high-energy beams Andrew Pype The HiRA group at the National Superconducting Cyclotron Laboratory (NSCL) set out to test a new system for identifying isotopes in heavy (Z~82) radioactive beams. The energy and velocity of each beam particle are used to establish its charge and mass. Gamma rays emitted by short-lived isomers are measured in coincidence. These characteristic gammas are then used to identify specific isotopes in an energy loss vs time-of-flight plot. In order to measure the energy loss of the beam, a gas ionization chamber collects electrons ionized by the beam passing through its gas volume. The electrons drift towards the anode along a constant electric field parallel to the beam, where the signal is amplified and digitized. A common problem faced with ionizing gas detectors is columnar recombination, where a liberated electron recombines with a positive ion. Because this is a stochastic process, it can adversely effects the energy resolution. The effect is explored for beams in the Pb region at high energy, up to 85 MeV/A. [Preview Abstract] |
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HA.00018: Neutron Interactions in GRETINA C. Hultquist, D. Weisshaar, J. Belarge, E. Kwan, T. Mijatovic, R. Titus, R.G.T Zegers, B.A. Brown, A. Gade, S. Lipschutz, J. Schmitt, C. Sullivan, E.M. Ney, J. Engel, D. Bazin, B. Elman, B. Longfellow, E. Lunderberg, P.C. Bender, C.M. Campbell, B. Gao, S. Noji, J. Pereira, J.C. Zamora GRETINA is a high-resolution $\gamma $-ray spectrometer consisting of segmented germanium crystal detectors that are subject to high-energy neutron damage via the destruction of the crystal lattice structure. Recently, GRETINA was used in a (t, $^{\mathrm{3}}$He$+\gamma )$ probe of the 86Kr nucleus, where a triton beam was accelerated towards Krypton gas cell, contained within two Kapton foils (C$_{\mathrm{22}}$H$_{\mathrm{10}}$N$_{\mathrm{2}}$O$_{\mathrm{5}})$. t(p,n)$^{\mathrm{3}}$He events from interactions with Hydrogen in the Kapton foil were isolated to study the interactions of neutrons in GRETINA.~Neutron-induced peaks and other phenomena were identified in the measured spectra from neutron events in the Germanium crystals. These experimental results will be compared to Geant4 simulations to study the efficacy of simulations to replicate neutron interactions in GRETINA. [Preview Abstract] |
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HA.00019: Neutron Unbound States in the N$=$20 Island of Inversion Robbie Seaton-Todd, Anthony Kuchera, Nathan Frank, John McDonaugh, Paul DeYoung, Wiiliam von Seeger, Thomas Baumann, Dayah Chrisman, Paul Gueye Radioactive beams are used to study the properties of neutron-rich nuclei out to the neutron drip line, particularly where the N$=$20 shell gap disappears, known as the ``island of inversion.'' This region is of interest because the mechanisms driving these changes in nuclear shell structure are not fully understood. An experiment at the National Superconducting Cyclotron Laboratory was conducted, using a $^{\mathrm{33}}$Mg secondary beam, to better characterize the structure of these exotic nuclei, by populating neutron-unbound excited states in this region. Experimental reaction targets in which rare nuclei and their decay are observed are made thicker for more reactions to occur or thinner for better energy resolution. To observe both good resolution and more reactions a segmented target comprised of alternating Be reaction targets and Si detectors was used. Additionally, the Modular Neutron Array, the Large multi-Institutional Scintillator Array (MoNA-LISA), and the Sweeper Magnet were used to perform invariant mass spectroscopy to reconstruct the decay energies of populated unbound states. Results, including decay energies of select nuclei, will be discussed. [Preview Abstract] |
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HA.00020: Uncertainty Estimates for Bound States, Resonances, and Scattering of Light Ions Benjamin Luna, Thomas Papenbrock The low-energy structure of neutron halo nuclei is well understood using effective field theories with zero-range interactions. However, this approach yields inaccurate results at leading order for charged-particle halos. We propose instead to describe the low-energy structure of charged-particle halos through a finite-range interaction potential. We use a two parameter delta-shell potential plus the Coulomb potential and compute charge radii, asymptotic normalization coefficients, scattering lengths, effective ranges, and scattering phase shifts for $\ce{^{6}\text{Li}}$, $\ce{^{7}\text{Li}}$, $\ce{^{7}\text{Be}}$, $\ce{^{8}\text{Be}}$, and $\ce{^{17}\text{F}}$. We also make an attempt to estimate uncertainties due to the adjustment of parameters to data and systematic model uncertainties. Our results agree with data within uncertainties, and we make several predictions. This opens the way to compute S factors of astrophysically relevant reactions with uncertainties. [Preview Abstract] |
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HA.00021: Study of Vibrations in the Nab Magnetic Spectrometer Hunter Presley The Nab experiment intends to precisely measure the beta decay correlation parameters `'a'' and `'b'' for the free neutron. The experiment is in the process of being commissioned on the Fundamental Neutron Physics Beamline at the Spallation Neutron Source of the Oak Ridge National Laboratory. The focal point of the experiment is the seven meter, superconducting, magnetic spectrometer which is used to measure electron energy and proton time-of-flight. The magnet is cooled to 4 kelvin by four mechanical cryocoolers positioned on the upper and lower half of the magnet. Each cold head contains a moving valve operating at about one hertz. The motion of these valves is coupled to the magnet and small amplitude vibrations can be felt by hand. If large enough, the vibrations will cause the detectors to move in the magnetic field, which gives rise to an additional source of noise. The detectors are located at the upper and lower end of the spectrometer. To evaluate the potential impact of the vibrations, an accelerometer was used to measure vibration spectrum for each cryocooler cold head and as well for both ends of the spectrometer. I'll describe the measurements where I used an Endevco model 2228B accelerometer read by a Hewlett Packard Spectrum Analyzer. I'll give results including reference measurement of floor vibration. [Preview Abstract] |
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HA.00022: Measuring the Properties of a Supersonic Gas Jet Target Mia Grace Cantrell, Kelly Chipps, Matthew Hall, Kate Jones Stellar explosions are the result of runaway nuclear reactions, but testing these reactions in the laboratory can be difficult. Supersonic gas jet targets can help us study some of these astronomical processes, because many of the nuclear reactions involve isotopes that only exist as gasses. The SOLenoid and Supersonic Target in Structure Experiments (SOLSTISE) experimental system at Oak Ridge National Laboratory has been made to test the implementation of a supersonic gas jet target inside a solenoidal spectrometer, like the Helical Orbit Spectrometer at Argonne National Laboratory. The design of a gas jet target system inside a solenoidal spectrometer is a difficult task, because shadowing of the reaction particles by the jet infrastructure must be minimized, and the vacuum pumps must be placed far away from the magnetic field. Tests are currently being conducted to minimize shadowing by testing different gas receiver cones, and measurements of the energy loss of alpha particles through the jet allow for the determination of jet density profiles for each cone. These preliminary jet density profiles and cone designs will be presented. [Preview Abstract] |
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HA.00023: Characterizations for a Mirror Neutron Search Taylor Dennis To date, there has been no conclusive evidence as to what kinds of particles make up dark matter. The nn' Collaboration has developed an experiment at the Spallation Neutron Source (SNS) to search for a possible dark matter candidate, mirror matter, by using a cold neutron beam. Using strong magnetic fields with high gradients, through a hypothetical transition magnetic moment, it is possible that a neutron may oscillate into its mirror neutron counterpart. After initial production, any mirror (sterile) neutrons will pass through a strong neutron absorber and then into another strong magnetic field where some may oscillate back and be detectable. Thus, the regeneration of neutrons from the mirror state, if the process exists in nature, can be discovered. I will present neutron beam characterizations, background analyses, and implications for statistical sensitivity limits for this beyond Standard Model search. [Preview Abstract] |
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HA.00024: Analysis of $\gamma $ p $\to $ p $\pi^{\mathrm{0}}\pi^{\mathrm{0}}$ Reaction at CLAS Miranda Carver Hall B of Jefferson Lab used the CEBAF Large Acceptance Spectrometer (CLAS) detector to study different properties of nuclear matter. One goal of studying nuclear matter is to understand the basis of the quark-quark interaction. Studying different particle reactions helps further this understanding, and adds to the overall knowledge of the field. The $\gamma $ p$\to $p $\pi^{\mathrm{0}}\pi^{\mathrm{0}}$ photoproduction reaction was measured using the CLAS detector at Jefferson Lab, where all the particles were detected. The aim of this study is to investigate $\gamma $ p$\to $p f$_{\mathrm{2}}$ (1270)$\to $ p $\pi^{\mathrm{0}}\pi ^{\mathrm{0}}$. The branching ratio of the f$_{\mathrm{2\thinspace }}$(1270) to $\pi^{\mathrm{0}}\pi^{\mathrm{0}}$ is 28{\%}. The f$_{\mathrm{2\thinspace }}$(1270) meson has been studied before but never via the $\pi^{\mathrm{0}}\pi^{\mathrm{0}}$ channel. This channel is unique because it does not have a dominant $\rho $ meson background which allows for the extraction of the f$_{\mathrm{2\thinspace }}$(1270) signal easily. Data for photoproduction of the f$_{\mathrm{2\thinspace }}$(1270) can be compared with theoretical calculations that include multi-gluon exchange between the incident photon and the proton target. By comparing data and theory, we will learn more about the role of gluons in the quark-quark interaction. In addition, the t distribution will be computed for photoproduction of the f$_{\mathrm{2\thinspace }}$(1270) meson, over incident photon energies from 3.5 to 5.5 GeV. [Preview Abstract] |
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HA.00025: Lifetime Measurements in $^{74}$As Colin Hawes, R. A. Haring-Kaye, K. D. Jones, K. Q. Le, J. D\"{o}ring, B. Abromeit, R. Dungan, R. Lubna, S. L. Tabor, P. L. Tai, Vandana Tripathi, J. M. VonMoss, S. I. Morrow The irregular signature-splitting pattern in the positive-parity band in $^{74}$As has recently been suggested to result from an underlying triaxial shape. Lifetime measurements could be used as a way to test this assertion, but so far they are unavailable for high-spin states. Thus the goal of this work was to measure as many lifetimes as possible in $^{74}$As using the Doppler-shift attenuation method in order to test the existing interpretation of its positive-parity structure. High-spin states in $^{74}$As were populated using the $^{14}$C($^{62}$Ni, $pn$) reaction at 50 MeV performed at Florida State University. Gamma decays were measured in coincidence using a Compton-suppressed array of 10 Ge detectors. Three lifetimes were measured within the positive-parity band and used to infer the quadrupole deformation parameter $\beta_2$ as a function of spin. The experimental $\beta_2$ values were then compared with theoretical ones extracted from total Routhian surface calculations. Although the experimental trend in the $\beta_2$ values are not reproduced by the calculations, the magnitudes of two experimental values are in agreement and triaxial shapes appear to be favored. [Preview Abstract] |
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HA.00026: Lifetimes Within the 73Se Nucleus Dexter Allen, R. Haring-Kaye, K. Jones, K. Le, J. Döring, B. Abromeit, R. Dungan, R. Lubna, S. Tabor, P.-L. Tai, Vandana Tripathi, J. VonMoss, S. Morrow There is considerable uncertainty in the literature regarding the cascade intensities of the decay sequences in $^{73}$Se. In particular, the degree to which each state is populated by side feeding can vary considerably. The goal of this work was to measure as many lifetimes as possible in $^{73}$Se by gating from above the transition of interest in order to eliminate the effects of uncertainties in side feeding intensities. This was made possible by the excellent $\gamma$-ray counting statistics for $^{73}$Se provided by the $^{14}$C($^{62}$Ni, 3$n$) reaction performed at Florida State University using a beam energy of 50 MeV and with a Compton-suppressed Ge detector array consisting of 3 Clover detectors and 7 single-crystal detectors. The Doppler-shift attenuation method was used to measure all lifetimes. Seven lifetimes were measured, four within the strongest positive-parity band and three within the favored negative-parity band. From these lifetimes the quadrupole deformation parameter $\beta_2$ could be inferred and compared with those predicted for these states as a function of spin. In general, the experimental trends were not reproduced in the calculations. [Preview Abstract] |
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HA.00027: Production of Nuclei on the Proton Dripline using MARS at Texas A&M University Isaiah Richardson Proton-rich nuclei at the proton dripline have been produced at beam energies of $>$77MeV/u at facilities such as GANIL and NSCL at Michigan State University. At Texas A\&M, our goal is to produce these proton-rich nuclei at energies around 40 MeV/u with beam from the K500 cyclotron, and separate these nuclei using the Momentum Achromat Recoil Spectrometer (MARS). We used a spectrometer simulator, LISE++, to devise an experiment with a $^{40}$Ca beam at 40 MeV/u on Be, Al, and Ni targets to determine how to optimally produce $^{35,36}$Ca. We tuned MARS to the parameters LISE++ predicted to see how much of these exotic nuclei we could produce in experiment. The products were detected with a $\Delta$E vs. E Si telescope to determine the yield of each isotope. It was concluded that at this energy, the Ni target had the highest production rate for the nuclei close to the proton dripline. The comparison between the experimental production rates and the production rates LISE++ predicted will be presented. [Preview Abstract] |
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HA.00028: Machine Learning:Potential Application for Particle Identification Parker Adamson, Mike Youngs In this project we examined the potential use of machine learning to significantly decrease the time required to analyze FAUST (Forward Array Using Silicon Technology) data without sacrificing the quality and confidence of the results. Networks of varying structure were first trained using SRIM which simulated perfect, 2{\%}, and 5{\%} detector resolution FAUST data. Each trained network was then tested on data disjoint from its training set of each resolution. Under the same procedure we trained and tested neural networks on real experimental data which had been identified using the traditional linearization method. This project establishes the validity and some constraints to the ultimate goal of this research, which is applying one network trained on data from a detector and then applying the network to further data from both that detector and other detectors, through the use of transfer learning, to expedite the analysis process. [Preview Abstract] |
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HA.00029: Production of X(3872) in Ultra Relativistic Heavy Ion Collisions Matthew Sibila, Ralf Rapp, Xiaojian Du The X(3872) particle, discovered in 2003 by the Belle collaboration, is of particular interest due to its structure being either a tetra-quark bound state or a molecular state. Its structure can be understood via an investigation of its production yields and spectra in Ultra Relativistic Heavy Ion Collisions (URHICs). We calculate the yields with a statistical hadronization model evaluating at either chemical freeze-out or kinetic freeze-out. The calculation is further extended with a rate-equation approach with its temperature-dependent hadronic width, accounting for its off-equilibrium production. Furthermore, the transverse-momentum spectra can be evaluated from a blastwave description. [Preview Abstract] |
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HA.00030: Extraction of bismuth from nitric acid media using 1-octanol and hydrophobic liquid binary mixtures Amy L. Vonder Haar, Evgeny E. Tereshatov, Charles M. Folden III $^{\mathrm{211}}$At is a promising nuclide for cancer treatment with a 7.2 h half-life and 5.9 MeV $\alpha $-emission. It is produced in a cyclotron by irradiation of metallic bismuth in the reaction $^{\mathrm{209}}$Bi($\alpha $, 2n)$^{\mathrm{211}}$At. However, prior to radiotherapy, astatine must be separated from the target. In order to perform this separation, bismuth behavior under astatine separation conditions must be understood and therefore is of medical relevance. To address this issue, the extraction of the radioactive tracer isotope $^{\mathrm{207}}$Bi (T$_{\mathrm{1/2}} \quad =$ 32.2 y) from varying nitric acid concentrations into an array of organic solvents is examined in this work. $^{\mathrm{207}}$Bi is used in place of $^{\mathrm{209}}$Bi due to the increased sensitivity the radioactivity of $^{\mathrm{207}}$Bi provides while maintaining the same behaviors in solution. The organic solvents used include 1-octanol and hydrophobic liquid binary mixtures consisting of combinations of \textsc{DL}-menthol, methyl anthranilate, ibuprofen, lidocaine, and Proton Sponge$^{\mathrm{TM}}$. For each solvent, the partition of $^{\mathrm{207}}$Bi between aqueous and organic phases has been measured and summarized in distribution ratio curves as a function of initial nitric acid concentration. The shape of these curves provides insight into the mechanism and efficacy of extraction. The results of this work will be presented. [Preview Abstract] |
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HA.00031: Measurement of proton quenching factors in p-terphenyl Miriam Matney, Cody Parker, Shuya Ota, Gregory Christian, Dustin Scriven, Stefania Dede, Michael Roosa The organic scintillator p-terphenyl (C$_{\mathrm{18}}$H$_{\mathrm{14}})$ is fast, bright, and provides excellent pulse-shape discrimination (PSD). These properties make p-terphenyl a versatile scintillator for use in neutron detectors. In order to characterize the scintillation efficiency of p-terphenyl for more accurate data collection, it is important to understand the amount of quenching as a function of particle energy. Quenching accounts for molecular de-excitation that does not result in the production of light in the scintillator. In this work, quenching factors were measured via a monoenergetic proton beam from the K150 cyclotron at the Texas A{\&}M University Cyclotron Institute at several energies from 3 MeV to 15 MeV. A 15-mm x 15-mm x 25-mm crystal of p-terphenyl was coupled to a photomultiplier tube and irradiated with a proton beam under vacuum. The quenching factor was determined by the relationship between the incident proton energy and the measured proton energy. [Preview Abstract] |
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HA.00032: Improved Waveform Analysis Techniques for Gamma Ray Spectroscopy Eric Lester The evolution of Population III stars has never been directly observed. Indirect techniques may provide crucial constraints on the proposed models of these stars. A planned experiment will study the $^7$Be$(^6$Li, d$)^{11}$C reaction to investigate the $^7$Be$(\alpha, \gamma)^{11}$C reaction rate for its contribution to the hot pp-chain. An important facet of this experiment will be the detection of gamma rays from the decay of states around the alpha threshold in $^{11}$C. The Texas CsI Array for Astrophysical Measurements (TexCAAM) has been created for this purpose, and this work concerns the testing of the device. Offline processing tools for digitized waveforms were developed and tested for potential energy resolution improvements over conventional ADC electronics. Other programs were created to determine angular correlations between successively emitted gamma rays and with an external deuteron signal. This software can be used in future experiments to not only to confirm the population of astrophysically important excited states in the $^7$Be$(^6$Li, d$)^{11}$C reaction, but also to constrain the spin and parities of other nuclei of interest. Developing results are presented, including a comparison of the methods developed in this work and conventional ADC techniques. [Preview Abstract] |
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HA.00033: Geometric analysis of three-body nuclei using Efimov physics Audrey Farrell, Aldo Bonasera, Hua Zheng The Thomas theorem describes loosely bound two-body quantum systems that become strongly bound as three-body systems, with a series of excited levels known as Efimov states. Using hyper-spherical geometries to describe two- and three-particle nuclei, we performed fits of total energy to known binding energies in order to determine the weighting of short-range potentials in a given interaction. When applying the appropriate scattering lengths and ranges to the system, we were able to replicate the binding energies of these nuclei with few fitted parameters. With this method, we tested various models for different light nuclei and compared which geometries reproduced the binding energy most accurately. Once we had performed enough fits to have estimates of the two-body potentials for systems of neutrons and protons, we extended our model by treating these systems as point particles in order to reproduce binding energies for heavier isotopes. Using this method we can make predictions of which experimentally measured binding energies correspond to Thomas and Efimov states. [Preview Abstract] |
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HA.00034: Dual-Axis Duo-Lateral Detector Signal Recreation Events Molly Aslin, Mike Youngs, Andy Hannaman, Sherry Yennello The dual-axis duo-lateral (DADL) silicon detector, used in the Forward Array Using Silicon Technology (FAUST), displays a particularly high position resolution and has previously been seen to minimize a “pin cushion” effect often seen in similar silicon detectors. However, it is estimated that 5\% of incident protons and 1\% of incident alpha particles are not picked up by the DADL detector and must be recreated manually. Using proton and alpha beams from the K150 cyclotron, we look to see how position on the detector affects signal resolution. We have isolated some extrema of a DADL detector using a brass mask, which will shield off most of the detector with the exception of selected edges and corners. By analyzing the full waveform for each incident particle, we are able to examine the locations where these contacts prove unreliable and verify how accurate our methods of signal recreation actually are. We have produced maps of position resolution for the DADL and as such, we are able to further characterize the position resolution on the detector. [Preview Abstract] |
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HA.00035: Radiation Damage Recovery of PbWO$_{\mathrm{4\thinspace }}$Crystals with Optical Bleaching Sean Oh Deeply Virtual Compton Scattering (DVCS) is the easiest way to study Generalized Parton Distributions, revealing correlations between spatial and momentum distributions of partons within a nucleon. An electromagnetic calorimeter is currently being designed for DVCS experiments in Hall C at Jefferson Lab in Virginia, USA. The calorimeter will consist of an array of 1080 PbWO$_{\mathrm{4}}$ crystals. PbWO$_{\mathrm{4\thinspace }}$crystals, known to be radiation-hard with good light yield, still undergo damage during radiation exposure; the crystal's light transmittance is reduced as a result, consequently lowering the energy resolution of the calorimeter. However, the radiation damage can be recovered by injecting blue light into the PbWO$_{\mathrm{4}}$ crystal, a method known as optical bleaching. The calorimeter will adopt this method to endure a high radiation environment in Hall C using crystal optical fibers and blue LEDs, which will also be used for detector calibration. I will present the performance of the optical bleaching system for the electromagnetic calorimeter, as well as the extent of radiation damage sustained by the optical fibers and LEDs. This work was conducted at the Institut de Physique Nucleaire d'Orsay, France during summer 2019 and supported by the National Science Foundation IRES Award No. 1658713. [Preview Abstract] |
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HA.00036: Efficiency Measurements for HPGe Detectors Megan Sturm, Gabriel Charles, Nourredine Hammoudi High Purity Germanium (HPGe) detectors are used for high-resolution gamma spectroscopy in nuclear physics. HPGe can be combined to construct full 4$\pi $ gamma-ray tracking detectors. For example, the GRETA (Gamma-Ray Energy Tracking Array) project in the USA will consist of 30 HPGe detectors for a total of 120 germanium crystals. Since each detector costs more than {\$}100,000, these detectors are typically bought through collaborations that maintain and repair them. When required, the detectors are moved to the experiment site for data collection and afterwards are returned to their home institution. The Institut de Physique Nucl\'{e}aire d'Orsay (IPNO), France is in charge of a pool of about 20 coaxial HPGe detectors. For each loan, several characteristics must be provided to users to create accurate simulations of their experiments. Previously, only the detector's resolution was provided. I will present an independent method I developed to measure the efficiency, peak-to-Compton ratio, resolution and corresponding uncertainties for each of the pool detectors. Additionally, this method can be used in the reparation of detectors through redefining their nominal voltage. This work was conducted at IPNO in the summer 2019 and supported by National Science Foundation IRES Award No. 1658713. [Preview Abstract] |
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HA.00037: Development of a System to Screen for PFAS Chemicals Using PIGE at Union College Colin M. Langton, Jacob E. Feinstein, Mia E. Villeneuve, Scott M. LaBrake, Michael F. Vineyard Per- and polyfluoroalkyl substances (PFAS) are man-made chemicals that have become a major environmental concern. They can be found in a broad range of products including food packaging, stain- and water-repellent fabrics, nonstick products, makeup, fire-fighting foams, and electronics. These chemicals do not break down easily in the environment, can bioaccumulate, and some can lead to adverse health effects. We are working on a system to screen for these chemicals using proton-induced gamma-ray emission (PIGE) in the Union College Ion-Beam Analysis Laboratory. Samples are bombarded in air with 1.8-MeV protons from the external beam facility on our 1.1-MV Pelletron tandem accelerator. The emitted gamma-rays are detected with a high-purity Ge detector. Currently samples are screened for the presence of PFAS chemicals within 3-5 minutes by looking for the characteristic fluorine gamma-rays at energies of 110 and 197 keV. Future work includes the development of a standards-based method to measure the concentration of fluorine in soil, water, and paper samples. We will describe our system and present preliminary results. [Preview Abstract] |
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HA.00038: Development of a Positron-Electron Annihilation Spectrometer to Characterize Defects in Crystalline Materials at Union College Jacob E. Feinstein, Colin M. Langton, Mia E. Villeneuve, Scott M. LaBrake, Michael F. Vineyard, Heather C. Watson Positron-electron annihilation spectroscopy is an analytical method for characterizing near surface defects on the atomic scale in crystalline samples of materials. Using a thin $^{\mathrm{22}}$Na source sandwiched between two samples, we will measure the lifetime of the positron and thus be able to characterize the number of defects in a sample from this lifetime. The lifetime of the positron (on the order of 0.4-2.0 nanoseconds) is determined from the time interval between the 1274-keV prompt gamma ray emission from the beta-plus decay of $^{\mathrm{22}}$Na into an excited state of $^{\mathrm{22}}$Ne and the subsequent annihilation of the electron and positron in the crystalline sample of interest by detecting the coincident 511-keV gamma rays.~ In the Union College Ion-Beam Analysis Laboratory (UCIBAL), we are currently constructing a system that will be used to measure the lifetime of the positron.~ We have successfully built, tested, and detected the coincident 511-keV gamma rays from the annihilation of electrons with positrons from the beta-plus decay of $^{\mathrm{22}}$Na. Preliminary results will be presented and future modifications to this setup will be discussed which will include the implementation and testing of faster electronics for the timing circuit that will be used to determine the lifetime of the positron. [Preview Abstract] |
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HA.00039: PIXE Analysis of Heavy Metals in Soil Along East River Mia E. Villeneuve, Jacob E. Feinstein, Colin M. Langton, Scott M. LaBrake, Michael F. Vineyard, Heather C. Watson We have performed a proton-induced X-ray emission (PIXE) analysis of soil samples collected along the East River in Queens, NY, at the Union College Ion Beam Analysis Laboratory (UCIBAL). Previous results for samples collected over a 5-km distance between Astoria Park and Gantry State Park show a spike in the Pb concentration to about 1500 ppm near the Hell Gate Bridge with a rapid decrease to \textless 500 ppm on either side of the bridge. We suspected that this spike is due to Pb-based paint used on the bridge when it was constructed in 1916. To investigate this, we collected samples at smaller distance intervals around the bridge, which were then dried, sifted into a fine powder and mechanically shaken for 24 hours to ensure a uniform mixture. Pellets were created by hydraulically pressing 0.5 grams of soil with a few drops of polyvinyl alcohol, then coated with a thin layer of Al and used as targets for the PIXE measurements. The samples were bombarded with 2.2-MeV proton beams from the Union College 1.1-MV Pelletron accelerator. X-ray spectra were measured with an SDD detector and analyzed with GUPIX software to determine the concentrations of heavy metals in the soil samples. We will discuss the sample collection and the analysis procedure and present the results. [Preview Abstract] |
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HA.00040: \textsc{RADIOACTIVE BETA-DECAY OF 133 INDIUM FOR NUCLEAR STRUCTURE STUDIES} Corey Halverson, Miguel Madurga \textsc{THE RAPID NEUTRON CAPTURE (R-) PROCESS FINAL YIELDS ARE DETERMINED BY WAITING POINT NUCLEI WHERE NEUTRON-CAPTURE AND PHOTO-DISINTEGRATION ARE IN EQUILIBRIUM. THE DECAY PROPERTIES OF THESE NUCLEI, HALF-LIVES AND NEUTRON BRANCHING RATIOS DETERMINE THE PATH OUT OF THESE WAITING POINTS. IN THIS WORK WE STUDY THE NUCLEAR STRUCTURE OF 133SN POPULATED IN THE BETA-DECAY OF 133IN. INDIUM 133 WAS CREATED IN INDUCED FISSION OF 238U AT THE ISOLDE FACILITY CERN. ITS DELAYED GAMMA AND NEUTRON EMISSION WAS OBSERVED AT THE ISOLDE DECAY STATION. PRELIMINARY RESULTS OF GAMMA AND NEUTRON EMISSION FROM UNBOUND STATES IN 133SN WILL BE PRESENTED.} [Preview Abstract] |
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HA.00041: Using the Glauber Monte Carlo Approach to Determine the Multiplicity and Eccentricity of Pb+Pb Collisions at the LHC Anya Wolterman Glauber models provide insight into the initial state of nuclear collisions by treating them in terms of the interactions of their constituent nucleons, in accordance with theories about the scattering of composite particles. These phenomenological techniques are commonly used to determine various geometric quantities associated with such femtoscopic many-body systems. The Glauber Monte Carlo approach uses a random impact parameter and measured nuclear densities to investigate quantifiable properties such as the particle multiplicity and the average geometric eccentricity for heavy ion collisions. The former involves the incorporation of a particle production model to plot the sum of the transverse energy, a measure of centrality. The latter delves into the eccentricity of different event classes, which can be used to characterize various collision shapes for measurements of elliptic flow of heavy mesons. The results of both applications can then be compared with analyses of real data from the Large Hadron Collider. [Preview Abstract] |
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HA.00042: A Study of Time Dependent Noise in the \textsc{Majorana Demonstrator} Waveforms Thomas Marshall, Anna Reine, John Wilkerson The \textsc{Majorana Demonstrator} is an array of high purity germanium detectors searching for neutrinoless double-beta decay in $^{76}$Ge and performing searches for beyond standard model (BSM) physics. The BSM searches are possible because of the \textsc{Demonstrator}'s low trigger threshold, below 1 keV. Such low thresholds can be sensitive to changing noise conditions. Understanding the nature of this noise is critical to our ability to perform BSM searches. An analysis of the RMS of waveform baselines in \textsc{Demonstrator} data helps provide better understanding of the electronic noise conditions present in the experiment so that potential issues can be identified and resolved. I present a comparison of the baseline RMS distributions in individual detectors before and after changes in noise, including an investigation of how changing noise conditions are correlated between different detectors. [Preview Abstract] |
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HA.00043: Determining the astrophysical $^{20}$Ne($\boldsymbol\alpha$,p)$^{23}$Na reaction rate using the Notre Dame 5U accelerator Alyssa Davis, Austin Mitchell, Dan Bardayan, Patrick O'Malley In binary star systems including at least one white dwarf, the companion star may accrete mass onto the white dwarf until electron degeneracy pressure can no longer support the additional mass. A threshold is surpassed at high accretion rates, causing a stellar explosion categorized as a type Ia supernova. The system undergoes nucleosynthesis throughout the mass transfer and supernova process, producing heavier elements. Uncertainties in the $^{20}$Ne($\alpha$,p)$^{23}$Na reaction rate have been shown to significantly affect the final abundances of a number of nuclei produced in type Ia supernovae. Although previous inverse kinematic measurements have been conducted to model this reaction rate, the explored beam energies were not of astrophysical significance. Utilizing the 5U vertical pelletron accelerator and the Rhinoceros extended gas target at the University of Notre Dame, new direct kinematic cross section measurements were conducted using beam energies as low as 3.5 MeV. Experimental methods and results will be discussed. [Preview Abstract] |
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HA.00044: Extraction of optical model parameters for $^{\mathrm{90}}$Zr($^{\mathrm{6}}$Li,$^{\mathrm{6}}$Li') at 60 MeV/u using a Markov Chain Monte Carlo algorithm Austin Smith, Kevin Howard, Umesh Garg The nuclear incompressibility is a fundamental property of nuclear matter which is critical for modeling astrophysical processes. The isoscalar giant monopole resonance (ISGMR) is the most direct means to extract the incompressibility from finite nuclei. $^{\mathrm{6}}$Li can be used in studies of the ISGMR with radioactive ion beams. However, before measurements with radioactive ion beams may begin, the optical model parameters for $^{\mathrm{6}}$Li scattering need to be determined. To determine the optical model parameters, the elastic angular distributions of the $^{\mathrm{90}}$Zr($^{\mathrm{6}}$Li,$^{\mathrm{6}}$Li') reaction were measured using the Grand Raiden spectrometer at the Research Center for Nuclear Physics at Osaka University. Experimental density distributions were used for the projectile and target nuclei to generate realistic volume potentials for the DWBA calculations. The optical model code, ECIS, and a Markov Chain Monte Carlo (MCMC) algorithm were employed to constrain the remaining optical model parameters for the reaction. The MCMC algorithm sampled from the 11-dimensional parameter space to visualize parameter probability distributions, from which the ideal optical model parameters were extracted. The results and implications for future work will be presented. [Preview Abstract] |
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HA.00045: A Method to Account for Hydroxide Contamination in Characterizing the Giant Monopole Resonance to Determine an Accurate K$_{\mathrm{\tau \thinspace }}$ Sierra Weyhmiller, Kevin Howard, Umesh Garg, Joe Arroyo, Hidetoshi Akimune, Kyoko Nosaka, Soumya Bagchi, Takanobu Doi, Yuki Fujikawa, Shintaro Okamoto, Mamoru Fujiwara, Tatsuya Furuno, Kento Inaba, Nobu Kobayashi, Shoken Nakamura, Zaihong Yang, Takahiro Kawabata, Nasser Kalantar-Nayestanaki, Muhsin Harakeh, Masatoshi Itoh, Yohei Matsuda, Shinsuke Ota Measurements on the isoscalar giant monopole resonance (ISGMR) in finite nuclei over a range of isotopes permit the extraction of K$_{\mathrm{\tau }}$, the nuclear incompressibility asymmetry term. K$_{\mathrm{\tau \thinspace }}$is critical to understanding proton/neutron asymmetric systems. A recent study has claimed that the energy of the ISGMR is higher in heavier calcium isotopes than lighter ones, indicating a positive K$_{\mathrm{\tau }}$. This is surprising when compared to most research on extracting finite nuclear incompressibilities from giant resonances. To independently verify the claim, a simultaneous study of the GMR of $^{\mathrm{40,42,44,48}}$Ca was conducted. However, contributions from hydroxide contamination were found in the $^{\mathrm{48}}$Ca foil used in the experiment. The methodology for accounting for the contribution of $^{\mathrm{16}}$O to the experimental spectra will be presented, and the implications will be discussed. [Preview Abstract] |
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HA.00046: The High Efficiency Total Absorption Spectrometer (HECTOR) and Correcting for Inconsistencies in \textsuperscript{27}Al(p,\(\gamma\))\textsuperscript{28}Si Sean Kelly, Anna Simon, Rebeka Kelmar, Orlando Olivas-Gomez, Craig Reingold, Alex Dombos, Patrick Millican, Jack Wurzer, Tessa Klein The processes responsible for producing heavy nuclei in stellar environments, such as the p-process and s-process, are studied by measuring radiative capture reaction cross sections. The High Efficiency Total Absorption Spectrometer (HECTOR) is a tool for measuring these small cross sections using the \(\gamma\)-summing technique. In order to study the efficiency of HECTOR, resonance strengths of the \textsuperscript{27}Al(p,\(\gamma\))\textsuperscript{28}Si reaction measured with HECTOR were compared to results from previous literature. HECTOR's results yield higher resonance strengths than previous works indicate, which may be due to incomplete cascade and branching information used in their calculations. Using a simulation of HECTOR in Geant4, it is possible to quickly calculate and edit cascades for \textsuperscript{28}Si at different resonances. By editing the cascade inputs of the simulation to agree with HECTOR's experimental data, it may become clear where and why previous literature underestimates \textsuperscript{27}Al(p,\(\gamma\))\textsuperscript{28}Si resonance strengths. [Preview Abstract] |
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HA.00047: Characterization of clover detectors for use in fIREBAll project Zarif Rahman, Kevin Lee, Wanpeng Tan, Ani Aprahamian, Shelly Lesher Measurement of conversion electrons is an important aspect of nuclear structure studies. A new fIREBAll (fInternal conveRsion Electron Ball Array) array is being constructed by building on the existing ``ICEBall'' mini-orange array of SiLi detectors. fIREBAll will come into existence from the replacement of the current array of six mini-orange Si(Li) detectors of ICEBall with twelve Si(Li) detectors to broaden the energy range of the detected electrons. fIREBAll will be used in conjunction with two Compton suppressed Ge detectors. Compton suppression shields of Bizmuth Germanate (BGO) will be used on two clover detectors for coincidence measurements of gamma-rays and conversion electrons. I have studied the clover detectors in order to characterize their efficiencies and resolutions. They were calibrated using $^{\mathrm{60}}$Co and $^{\mathrm{252}}$Eu sources and a digital DAQ system. Each of the four crystals for each clover detector were evaluated separately and in summing of all four quadrants. This work is based on the full characterization of the energy resolution and the detection efficiency of the two clover detectors envisioned for use with fIREBAll. [Preview Abstract] |
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HA.00048: Lifetime measurement of the 6.79 MeV state in $^{\mathrm{15}}$O Lexanne Weghorn, Bryce Frentz, Ani Aprahamian, Wanpeng Tan, Zarif Rahman, Jack Enright, Kevin Lee, Christina Dulal, Michael Wiescher, Joachim Goerres, Kevin Howard, Samuel Henderson, Shane Moylan, Beka Kelmar The $^{\mathrm{14}}$N($p,\gamma )^{\mathrm{15}}$O reaction is one of the time-limiting reactions in stellar evolution and the burning of protons to heavier elements known as the CNO cycle. This rate is in turn dependent on the lifetime of the 6.79 MeV state in $^{\mathrm{15}}$O. In preparation for a lifetime measurement of the 6.79 MeV state in $^{\mathrm{15}}$O, targets were prepared by implanting different doses of $^{\mathrm{14}}$N into tantalum, tungsten, and molybdenum backings at beam energies of 350 keV. The targets were produced, and subsequently studied using the 5 MV Sta. Ana accelerator at the University of Notre Dame Nuclear Science Laboratory. The characteristics of the targets were determined using the 1058 keV resonance in $^{\mathrm{14}}$N($p,\gamma )^{\mathrm{15}}$O, which also served as a feasibility test for the lifetime measurement. Varying the backing material and implanted dose of the targets will allow the identification of systematic trends in the data. The lifetime measurement will be made in an upcoming experiment using the Doppler-Shift Attenuation Method. There have been several former attempts to measure this lifetime with limited determination of upper limits. Information about the production and the properties of the targets will be presented, as well as preliminary results from the lifetime measurement. [Preview Abstract] |
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HA.00049: \textbf{St. George detector simulation to identify source of contaminant nuclides} Angel Garcia-Simental, Jerry Hinnefeld, Shane Moylan, Manoel Couder The St. George recoil mass separator at the University of Notre Dame is used to measure cross sections of astrophysically important alpha-capture reactions. The St. George detection system, which uses measurements of energy and time-of-flight to identify reaction products and residual beam particles reaching the end of St. George, also detects other nuclides. Possible sources of these nuclides are contamination in the recirculated helium used as a gas jet target or contaminant beams from the accelerator ion source itself. A GEANT4 simulation of the St. George detector system is being used to determine the source of the detected contaminants, as well as other artifacts in the time-of-flight vs. energy plots. [Preview Abstract] |
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HA.00050: Characterization of CeBr$_{3}$ Scintillation Detectors for use in Coincidence Measurements Jack Enright, Wanpeng Tan, Ani Aprahamian Coincidence measurements play an important role in nuclear experiments. The advantages of CeBr$_{3}$ scintillation detectors over the more commonly used LaBr$_{3}$ and HPGe detectors in the detection of gamma-rays such as in $^{12}$C+$^{12}$C measurements are shown. The coincidence technique is required for the carbon fusion reaction in order to measure its cross section at energies well below the Coulomb barrier. The usefulness of CeBr$_{3}$ scintillation detectors for the most important energies of astrophysical $^{12}$C+$^{12}$C fusion processes ($1-3 MeV$ in the center of mass) is discussed. The results of a gamma-gamma coincidence set-up for $^{60}$Co including two CeBr$_{3}$ scintillation detectors from Berkeley Nucleonics are reported. The results of a gamma-neutron coincidence experiment for $^{252}$Cf using the aforementioned CeBr$_{3}$ detectors alongside lithium glass and liquid scintillators are shown also. [Preview Abstract] |
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HA.00051: \textbf{Improving the efficiency of the St. George detector system by recovering anomalous events} Gustavo Duran, Jerry Hinnefeld, Luis Morales, Manoel Couder The St. George recoil mass separator at the University of Notre Dame is used to study the process of nucleosynthesis in the course of stellar helium burning by measuring cross sections for low energy ($\alpha $,$\gamma )$ reactions induced by heavy ions in inverse kinematics. The use of inverse kinematics ensures the reaction products are at far forward angles, where they can be efficiently detected. St. George separates the reaction products from the unreacted beam particles that exit the target in the same direction at a rate orders of magnitude higher than the product of interest. Some unreacted beam particles do reach the end of St. George, where ions are identified by measuring their energy and their time-of-flight over a known distance. Time-of-flight is measured with a pair of transmission detectors utilizing microchannel plates and the energy is measured in a silicon strip detector. A fraction of particle detections suffer from too-low energy signals in the silicon detector. These events are being studied using the ROOT data analysis framework, with the hope that the corresponding particle can still be unambiguously identified. [Preview Abstract] |
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HA.00052: \textbf{Improving LANCE, the ETACHA user interface for the St. George recoil mass separator} Stephanie Tallman, Jerry Hinnefeld, Michael Kurkowski, Chris Seymour, Manoel Couder The St. George recoil mass separator at the University of Notre Dame, used to study nucleosynthetic ($\alpha $,$\gamma )$ reactions induced by low energy, low Z heavy ions, delivers reaction products in a single charge state to the detection system at its end. The distribution of charge states of reaction products emerging from the helium gas jet target must be known in order to extract the total reaction yield from the yields of the one or two most abundant charge states, which are in practice all that can be measured when the cross section is low. The program ETACHA is used for charge state calculations, and its predictions are compared here to measured distributions for nitrogen and fluorine. LANCE, a code written in python, serves as a front-end that simplifies and automates use of the ETACHA program. Further development of LANCE ensures the viability of ETACHA, particularly in cases where gathering experimental data on charge state distribution is difficult or impossible. [Preview Abstract] |
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HA.00053: Impact of Neutron Induced Fission on r-process Nucleosynthesis Calculations Lauren Ward, Nicole Vassh, Trevor Sprouse, Rebecca Surman Recent evidence indicates that the r process, which is responsible for the creation of the heaviest elements in the universe, occurs at the site of a neutron star merger. Within such merger environments fission has the potential to be greatly influential on abundance yields of nucleosynthesis calculations. We perform sensitivity studies that look at how changing individual neutron induced fission rates and yields affect the abundances of such calculations. We do this for two distinct sets of theoretical nuclear data (based on FRDM 2012 and HFB-17 masses, respectively) and then relate the result to the fission barrier predictions for both models. Additionally, we perform Monte Carlo variations of all of the fission rates to determine the potential uncertainty range in these nucleosynthesis calculations given two distinct fission yield prescriptions (simple symmetric split and GEF). We find that varying the properties of neutron induced fission have a dramatic impact on r-processes nucleosynthesis yields and require further study. [Preview Abstract] |
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HA.00054: Exotic Triaxial Shape and Wobbling Rotational Motion in 189Au Joseph Cozzi, Nirupama Sensharma, Umesh Garg, Kevin Howard While most nuclei are symmetrically shaped, exotic asymmetric shapes have been observed in the excited nuclear states of heavy mass nuclei. One such asymmetric shape, the triaxial shape, is characterized by three different lengths for each of the three primary axes. Due to the asymmetry in its shape, an excited triaxial nucleus spins irregularly. This non-uniform rotational motion is known as `wobble' and results in the emission of highly mixed electric and magnetic gamma rays as the nucleus transitions from higher to lower rotational energy states. Excited 189Au nuclei were created through a dehydration fusion reaction performed at Argonne National Laboratory. Gammashpere, an array of 110 high purity germanium detectors housed at Argonne, was used to capture the gamma ray decay spectrum from the excited 189Au. This spectrum is being analyzed in order to confirm and expand upon previously published level schemes of 189Au. Directed coefficients of orientated nuclei and angular distributions will be calculated and used to identify the polarity and electromagnetic characteristics of key transitions in the 189Au gamma ray decay spectrum. The level scheme and analysis results from this study on the nuclear shape and rotational motion of 189Au will be presented. [Preview Abstract] |
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HA.00055: Superallowed alpha decays near 100Sn - detector development for measurement of the 104Te lifetime Ian Cox, Robert Grzywacz, Thomas King, Krzysztof Rykaczewski, Joe Heideman, Rin Yokoyama, Cory Thornsberry, Maninder Singh An experiment using a YSO implant detector, along with LaBr$_3,$ HAGRiD detectors, is planned to measure the alpha decay chain of $^{108}$Xe to doubly magic, $^{100}$Sn. Previous attempts to measure the half-life of $^{104}$Te resulted in an upper limit of 20ns. The fast scintillation response of the YSO detector will aim for an accurate measurement of the half-lives of both $^{108}$Xe and $^{104}$Te. The result will enable determination of the alpha particle pre-formation factor. Development of the new segmented YSO detector designed for this experiment will be presented. [Preview Abstract] |
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HA.00056: Developing all-in-one SiPM package arrays for Nuclear Instrumentation Donnie Hoskins, Zhengyu Xu, Miguel Madurga Flores The rapid development of Silicon PhotoMultipliers (SiPM) has made them a very attractive solution to read out scintillator materials. Moreover, SiPM are by nature very resistant to extreme environments at low temperatures, low pressures, or high magnetic fields. Most commercial solutions simply integrate arrays of several small SiPM with common cathode and individual anodes readouts. They require external preamplifier solutions, with dedicated connections that will be prone to electronic pickup and noise. We have developed highly integrated SiPM package, including on-board preamplifiers, for a variety of nuclear instrumentation needs. Here we will present the first results of the board performance using EJ-200 plastic scintillators and LaBr(Ce) Brilliance. Using a compact 4x4, 24x24 mm\textasciicircum 2 array with LaBr(Ce), we obtain a 4.5{\%} energy resolution at 667 keV, remarkably similar to the larger 36x36 mm\textasciicircum 2 array developed for the apollo array at HELIOS [1]. [1] J.C. Lighthall et al, Nucl. Intr. Methods A622, 97 (2010) ; https://www.phy.anl.gov/atlas/workshop14/APOLLO.pdf [Preview Abstract] |
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HA.00057: Effects of Radiation on FR4 Printed Circuit Boards Kevin Scheuer, Ricardo Alarcon, Jason Holmes, Evgeny Galyaev, David Blyth Printed Circuit Board applications in high dose rate environments are becoming more common, and considerable research exists on how electrical devices attached to the PCB respond to varying degrees of radiation. An understanding of how the PCB substrate itself reacts is lacking though, particularly for FR4, one of the most common substrates used. The following study presents measurements of electrical and physical parameters for a variety of FR4 substrates, and the respective changes following exposure to a \small{$3.38 * 10^{16}\ n/cm^2$} total neutron fluence, in The Ohio State's Nuclear Reactor Laboratory Auxiliary Irradiation Facility (AIF) vertical dry tube. Consequently, selection of a PCB substrate is shown to be of consideration beyond the typical frequency dependant parameters, especially for environments where high physical stress or flammability are of concern. [Preview Abstract] |
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HA.00058: Study of Neutron-rich Nuclides of Z $=$ 13, 12 John McDonaugh, Nathan Frank, Robbie Seaton-Todd, Anthony Kuchera, Paul Gueye, Paul DeYoung Neutron-rich nuclides show features not observed in stable nuclides indicating changes in nuclear structure. Certain regions of the chart of nuclides are of particular interest such as the ``islands of inversion.'' An experiment to produce nuclides in highly excited states was performed at the National Superconducting Cyclotron Laboratory. A $^{\mathrm{48}}$Ca beam collided with a beryllium production target, which produced multiple secondary beams such as $^{\mathrm{34}}$Al and $^{\mathrm{36}}$Si. These beam nuclides impinged on a segmented target consisting of alternating Si-PIN detectors (4 total) and beryllium targets (3 total) producing many nuclides in highly excited states that resulted in a charged fragment and one or more neutrons being emitted. Using a superconducting dipole magnet, the charged fragments were swept into several charged particle detectors while the neutrons were measured as they interacted with arrays of scintillating plastic bars called the MoNA-LISA. The fragments and the emitted neutrons are detected in coincidence and their detected properties may be pieced together by invariant mass analysis to determine the energy of the neutron-unbound nuclide prior to decay. The results of the analysis for neutron detection, isotope separation, and the energy reconstruction of the decayed nuclides will be presented. [Preview Abstract] |
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HA.00059: Characterizing a Charged Particle Detector Telescope Georgia Votta, Nathan Frank, Thomas Baumann, James Brown, Paul DeYoung Performing experiments on neutron-unbound nuclei requires the detection of a neutron, a charged particle, and in some instances, gamma rays. The development of a charged particle detector telescope will facilitate the detection of these particles for future experiments performed at the National Superconducting Cyclotron Laboratory at Michigan State University. This system will allow charged particle detection along with efficient detection of gamma-rays by a device like the CAESium-iodide scintillator ARray (CAESAR) and neutrons with the Modular Neutron Array (MoNA). In order to construct this system, each charged particle detector (Si-PIN, position sensitive Si, or CsI(Tl)) needs to be tested to ensure each detector's response along its area is uniform and to verify the manufacturers' specifications. The construction of a raster scanner facilitates the process of the position-dependent testing inside a grounded metal box. The raster scanner consists of two stepper motors controlled by Arduino software that allow a $^{\mathrm{210}}$Po source to be reproducibly transported across the surface of each detector and a mask that collimates the direction of the alpha particles. Results of detector characterizations will be presented. [Preview Abstract] |
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HA.00060: Design and construction of an MR-TOF-MS for the CHIP-TRAP Penning trap mass spectrometer at Central Michigan University Philip Snoad, Ramesh Bhandari, Nadeesha Gamage, Madhawa Horana Gamage, Matthew Redshaw High precision mass measurements are vitally important in a wide range of fields, such as nuclear structure, nuclear astrophysics, neutrino physics, metrology, and tests of fundamental physics. At Central Michigan University we are developing a Penning trap mass spectrometer (CHIP-TRAP) for high-precision mass measurements with stable and long-lived isotopes e.g. for a measurement of the $^{163}$Ho EC Q-value to aid direct neutrino mass determination experiments, and the $^{36}$Cl neutron separation energy that, in combination with precise $\gamma$-ray spectroscopy measurements will enable a test of $E = mc^{2}$. To aid in the efficient preparation and transport of ions from radioactive and low abundance isotopes, we are designing a multi-reflection time-of-flight mass-separator (MR-TOF-MS) to increase the path length of ions as they travel from our ion sources to the Penning trap. In this presentation, I will show results from simulations of ion transport through our MR-TOF-MS that indicate our design goal of a resolving power R $>$ 20,000 is achievable. I will describe the design of the MR-TOF-MS and report on the status of the fabrication, assembly, and commissioning of the apparatus. [Preview Abstract] |
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HA.00061: Magneto-Ionization Spacecraft Shield for Interplanetary Travel: Conceptual Design Lorien MacEnulty, David Atri, Sean Cusick, Doug Drake, Keegan Finger, Luke Hofmann, Trace Johnson, Julie Lafranzo, Aurora Lyon, Daniel Madison, Molly McCord, Athanasios Petridis, Gavin Menning, Melanie Schnurr, Will Thomas A central issue facing manned interplanetary travel is intense radiation exposure to solar wind and cosmic rays. MISSFIT is dedicated to conceptually developing a shield that combines passive and active shielding similar to Earth's magnetic field and ionosphere. The system will focus and absorb low-energy particles and deflect high-energy particles. Subgroups are assigned tasks to investigate multiple components of the system, including the motion of charged particles in complex magnetic fields, preferable structures of magnetic fields, energy loss in ionization of gases, and the composition of solar wind and cosmic rays. We will present results pertaining to various shapes and intensities of magnetic field coupled with the effects of those fields on particle trajectory calculations. Furthermore, we will expand on our experimental analysis of gamma ray attenuation in Demron and Vectran, fabrics that claim high radiation protection properties. Upon completion of a conceptual design, funding from NASA to proceed with a technical design will be pursued. [Preview Abstract] |
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HA.00062: Magneto-Ionization Spacecraft Shield For Interpanetary Travel: Radiation Absorbtion Experiments Trace Johnson, Lorien MacEnulty, Sean Cusick, William Thomas, David Atri-Schuller, Melanie Schnurr, Julie Lafranzo, Athanasios Petridis, Doug Drake, Keegan Finger, Daniel Madison, Gavin Menning, Molly McCord, Luke Hofmann An important consideration when humans make the journey to Mars is exposure to high radiation levels. Our conceptual design for a spacecraft radiation shield consists of two parts. The active shield is a magnetic field capable of deflecting or funneling the charged particles to areas of strong field. The passive shield consists of gas-filled bubbles placed at strong-field regions that absorb energy from funneled particles by ionization and scattering. An important feature of our group’s work are experiments conducted to determine the ability of various materials to block radiation. We tested the materials Demron and Vectran which will hold the ionization gases. Our experiments consisted of capturing a radiation absorption spectrum at various material thicknesses. Materials were exposed to radiation from several sources at varying energies. Each X-ray and gamma-ray peak from the spectrum of charged particles was fit with a Gaussian and the attenuation length was determined. The materials showed promise for blocking X-rays, but had difficulty stopping Gamma-rays. [Preview Abstract] |
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HA.00063: Quantifying Liquid Argon Neutrino Detector Sensitivity to Supernova Burst Neutrinos Crystal Burgos, Kate Scholberg We produced figures of merit that show how many neutrinos can be detected for supernovae as a function of distance and compactness. Compactness is the ratio of the mass contained within the radius of the progenitor at the time of core bounce as defined by O'Connor and Ott (2011). This was used to quantify the sensitivity of a 40-kiloton liquid argon detector to core-collapse supernovae. We calculated neutrino event rates for a range of compactnesses. Compiling the results of the neutrino fluxes with a probability distribution of supernovae with respect to compactness and a probability distribution of supernovae with respect to distance allows the generation of useful data visualizations. Specifically, it produces a histogram that shows the number of neutrinos likely to be detected as well as the probability of seeing core-collapse supernovae as a function of both compactness and distance. With these histograms, we are able to determine how many models can be observed given a neutrino event threshold for this type of detector. These methods can be repeated for other types of detectors in the future. [Preview Abstract] |
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HA.00064: Mixture density networks as a machine learning technique for QCD analysis Meg Houck, Eleni Tsitinidi, Manal Almaeen, Yasir Awadh Alanazi, Michelle Kuchera, Yaohang Li, Wally Melnitchouk, Raghu Ramanujan, Nobuo Sato The use of machine learning in QCD analysis is an example of how learning techniques can facilitate the interaction between experimental data and QCD theory. In this project a mixture density network (MDN) was developed as a tool for QCD data analysis, providing one solution to the inverse problem using machine learning. The MDN is used to generate maps between experimental observables and theoretical parameters, taking experimental cross sections as inputs and generating parameters that describe the data in terms of the underlying parton distribution functions. To accommodate the possibility of multiple solutions in the theoretical parameter space when experimental data have large uncertainties, the MDN predicts a probability distribution function representing the multiple solutions and their likelihood. The results for the "up" and "down" quark distributions for the case of a 10-dimensional toy problem will be presented. [Preview Abstract] |
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HA.00065: Using a mixture density network to interface between experimental observables and QCD theory Eleni Tsitinidi, Meg Houck, Yasir Alanazi, Manal Almaeen, Michelle Kuchera, Yaohang Li, Wally Melnitchouk, Raghu Ramanujan, Nobuo Sato We map experimental high-energy scattering data to quantum probability distributions that characterize nucleon structure and the emergence of hadrons in terms of the quark and gluon degrees of freedom of QCD. We train a mixture density network (MDN) to address the inverse problem of transforming observable space into theoretical parameter space. The output of the network provides a mixture of Gaussians that is processed through a mode-finding algorithm to produce multiple points in parameter space with their probabilities. This approach has been used to accurately predict collinear parton distribution functions, and can be straightforwardly extended to other probability distributions, such as generalized parton distributions and Wigner functions. It will thus allow us to build a new generation of QCD analysis tools that will provide a new paradigm for the analysis of high-energy data and the design of future experiments. [Preview Abstract] |
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HA.00066: Using Adversarial Networks for Data Processing in the Hall B Drift Chamber Andrew Hoyle, Jose Cruz, Gagik Gavalian, Michelle Kuchera, Raghu Ramanujan The image to image translation software Pix2Pix was used to format track data produced by the drift chamber at Hall B at Jefferson Lab. This track data came in the form of images containing particle trajectories from different drift chamber channels. While Pix2Pix is typically used to generate realistic images of objects based on sketches, we trained the model to eliminate unwanted noise data from within each event. This was done using a training dataset containing pairs of track images, one containing all data recorded by the detector in one event, and one containing only the desired track. We explore the most effective architecture and tuning parameters to give the desired results. Results will be presented alongside metrics showing how accurate generated images are to the desired output. [Preview Abstract] |
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HA.00067: Track Selection In Drift Chambers Using Convolutional Neural Networks Jose Cruz, Andrew Hoyle, Gagik Gavàlian, Michelle Kuchera, Raghu Ramanujan Particle tracks of interest were selected from Hall B data at Jefferson Lab using machine learning methods. This research uses convolutional neural networks (CNNs) to classify which signals within an event belongs to the particle of interest. Using CNN architectures common in image analysis, we trained our model using data where the track are known. We tested VGG16, VGG9, Xception , InceptionV3, MobileNetV2 and InceptionResNetv2, the CNN architectures starting with pre trained weights to determine which model will provide the best results. The goal is to find the model and setting that provides the most efficient and accurate results with analyzing images at a speed of 3 milliseconds per image or lower. Results will be presented with comparisons between different models in terms of speed,loss, and accuracy. [Preview Abstract] |
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HA.00068: Using Deep Learning to Aid Track Reconstruction in the Active-Target Time Projection Chamber John Blue, Dulce Pacheco, Michelle Kuchera, Raghu Ramanujan, Yassid Ayyad, Daniel Bazin, Wolfgang Mittig, Jaspreet Randhawa, Robert Solli Machine learning methods were used to aid track reconstruction in the Active-Target Time Projection Chamber (AT-TPC) at the National Superconducting Cyclotron Laboratory in Michigan State University. The AT-TPC is a gas-filled detector where the gas is both the scattering target and detection medium, allowing for three-dimensional reconstruction of reaction target tracks. During the recently run $^{22} \text{Mg} (\alpha,\text{p})$ experiment, $45\%$ of the pads comprising the AT-TPC’s sensor plane were overbiased, resulting in particle tracks with significant discontinuities. In an effort to make these broken tracks suitable for event classification and analysis, we used deep learning techniques, including fully-connected neural networks and an implementation of a context encoder neural network architecture developed by Pathak et al. for image inpainting. Preliminary results have shown the context encoder to be successful at inpainting simulated particle tracks in the AT-TPC. A comparison of methods as well as reconstructed tracks in two and three dimensions generated by the networks will be presented. [Preview Abstract] |
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HA.00069: Automated Histogram Comparison Improvements for the NIFFTE FissionTPC Christine Case The Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) collaboration aims to make high-precision $^{239}$Pu(n,f)/$^{6}$Li(n,t)$\alpha$ cross section ratio measurements with quantified systematic uncertainties at Los Alamos National Laboratory. The experiment incorporates fixed targets surrounded by a fission Time Projection Chamber (TPC). This fissionTPC enables 3D reconstruction of tracks from charged particles that ionize the TPC gas. During data collection, shifters inspect dozens of histograms visually to monitor detector performance and data quality. Currently, the Kolmogorov-Smirnov (KS) statistic quantifies histogram similarity. One challenge for applying KS to fissionTPC data is comparing histograms that include spontaneous alpha decay background and beam induced events that depend on beam intensity. Thus, the NIFFTE software is being updated with additional automated histogram comparisons. This presentation will include updates and modifications to the previous KS statistic and the new automatic histogram comparison program. [Preview Abstract] |
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HA.00070: Designing an Integrated Data Acquisition System for a Modular Cosmic Ray Test Stand Kolby Kiesling The modular cosmic ray test stand (CRTS) is an array of plastic scintillators with photo-multiplier tubes (PMTs) used to determine efficiencies of prototype detectors using cosmic ray muons. The CRTS is a fully adjustable detector array using 80/20 with two shelves of four scintillators, each one 20 cm by 180 cm in size, with PMTs attached to both ends. Development of a VME-based data acquisition system (DAQ) has started with goals to benchmark prototype detectors at Abilene Christian University for use at national laboratories. The VME DAQ is composed of a NIM constant fraction discriminator, MCFD-16, which splits ECL out signals to a VME time to digital converter, MTDC-32, and VME charge density integrator, MQDC-32. The Wiener VM-USB is used for event execution and readout on the VME bus. Additionally, a Wiener MPODC is used to control the voltage supply to the PMTs. To monitor the behavior of the equipment as well as quality of data that is collected, MIDAS software has been utilized. This presentation will describe the design process of developing the MIDAS-based DAQ and its early implementation. [Preview Abstract] |
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HA.00071: Manufacturing Scintillator Tiles for the STAR Forward Upgrade Lilian McIntosh Over the last 20 years, Relativistic Heavy Ion Collider (RHIC) experiments at Brookhaven National Laboratory (BNL) have studied the strong interaction through collisions between subatomic particles and nuclei. The Solenoidal Tracker at RHIC (STAR) plays a leading role in providing information regarding the proton structure, properties of the constituents, and their interactions. The STAR Forward Upgrade will enhance its capabilities by creating new low-angle subsystems, including a forward hadronic calorimeter system (HCal). The HCal, as well as a new forward tracker and electromagnetic calorimeter, will enable new low-angle measurements at STAR, including forward jet, dijet, and hadron-in-jet production. Abilene Christian University$'$s (ACU) contribution to the construction of the HCal entails cutting and polishing 6,300 plastic scintillator tiles to the specifications of the upgrade. In recent years, ACU has invested in new facilities that allow this large-scale production to be completed on campus for the first time. A manufacturing process tailored to these facilities was developed to obtain optimal production efficiency and meet the specifications required for the upgrade. The specific process will be presented, including the scintillator cutting and polishing techniques. [Preview Abstract] |
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HA.00072: The E1039 drift chamber Cosmic Ray Commissioning Yves Ngenzi SpinQuest/E1039 is a fixed-target Drell-Yan experiment using the Main Injector beam at Fermilab, in the NM4 hall. It follows up on the work of the Nusea/E866 and SeaQuest/E906 experiments at Fermilab that sought to measure the d/u ratio on the nucleon as a function of Bjorken-x. By using transversely polarized targets of NH3 and ND3,SpinQuest seeks to measure the Sivers asymmetry of u bar and d bar quarks in the nucleon; a novel measurement aimed at discovering if the light sea quarks contribute to the intrinsic spin of the nucleon via orbital angular momentum. The E1039 Drift Chamber Cosmic Ray Commissioning will be discussed. Cosmic ray datasets were used to understand noise issues and to set nominal HV settings and thresholds for later beam runs. In addition to that, noise was a problem in drift chamber. Therefore, to reduce readout noise we studied the effect of adding ferrite cores to different readout cables; the result of adding ferrite will also be discussed. [Preview Abstract] |
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HA.00073: Improving Function of Wire Chambers for E1039 Elizabeth Jennings E1039 at Fermi National laboratory is seeking to better understand the contribution of quark-antiquark pairs to nucleon spin. E1039 will utilize a 120GeV unpolarized proton beam and collide it with an 80\% transversely polarized target to probe sea quarks in said target, in contrast to most other experiments which are sensitive to the valence quarks. The tracking of dimuon pairs produced via the Drell-Yan process in this collision will allow for the measurement of left-right spin asymmetries of those produced pairs, which in turn facilitates the isolation of the Sivers function. E1039’s wire chambers are essential to this measurement, as they allow for the recording of precise locational data of the relevant charged particles which pass through them. To ensure that these chambers are operating at peak efficiency, the first needed improvement was to reorganize all readout cables to remove a ground loop. Additionally, the environmental monitoring system was repaired to study correlations between noise and leakage currents in the wire chambers. The repair and utilization of the environmental monitoring system for the wire chambers will be presented, as well as analysis of data taken using that system relating environmental conditions and leak current levels in the chambers. [Preview Abstract] |
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HA.00074: Analysis of Hodoscope Efficiencies for E1039/SpinQuest Spectrometer using Cosmic Rays Nate Rowlands SpinQuest (E1039) at Fermi National Accelerator Laboratory is trying to help understand the spin structure of the nucleon sea using the 120 GeV proton beam and polarized NH$_{3}$ and ND$_{3}$ (ammonia) solid targets to provide the polarized hydrogen and deuterium. It uses the Drell-Yan process to access the nucleon sea via quark-antiquark pairs annihilating into a virtual photon, which decays into a $\mu^+$ $\mu^-$ pair. Scintillator hodoscope planes provide the primary trigger, so understanding their efficiency is critical for the science goals of SpinQuest. This is achieved by counting the number of single track events that hit all eight planes vs the events with hits in seven or fewer planes. The goal is to have 99$^{\%}$ efficiency for every hodoscope plane. Initial studies of this technique are being done using cosmic rays. This analysis will measure efficiencies for single muon events. Thus a verified technique of measuring hodoscope efficiencies will be in place when SpinQuest begins engineering runs by November, 2019 and data taking by early 2020. [Preview Abstract] |
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HA.00075: CLAS12 Drift Chamber Reconstruction Code Validation Michael Armstrong, Gerard Gilfoyle, Veronique Ziegler Jefferson Lab's upgraded CLAS12 detector studies the quark-gluon structure of hadrons with electron scattering experiments. The CLAS12 software reconstructs particle events collected by CLAS12 or simulated. Upgrades to its more than 84,000 lines of executable code are validated on a nightly basis with unit tests that apply it to a standard data set. Scattered electrons bend in the CLAS12 magnetic field leaving tracks in drift chambers (DC). The reconstructed trajectory is used to determine momentum and vertex position. The raw data (e.g. ADCs) for a single event are stored in the code, reconstructed, and compared to standard values. As the software evolved the previous DC test would signal a failure when the reconstruction was done properly. Recent improvements had changed the momentum reconstruction so it was outside the acceptable range. We also discovered a large discrepancy with the vertex position. To fix the test we simulated momentum and vertex distributions using the CLAS12 Common Tools and extracted the reconstruction resolution. We generated new, simulated raw data for a single event, redefined the acceptable momentum ranges, and added a new requirement on the vertex. The results have been tested and incorporated into the Common Tools. [Preview Abstract] |
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HA.00076: Improving the Particle Multiplicity Generator Model for the Empirically Trained Hadronic Event Regenerator Luisa Velasco, Randall McClellan, Wally Melnitchouk, Nobuo Sato, Yaohang Li, Yasir Alanzi, Michelle Kuchera, Michael Robertson, Evan Pritchard, Tianbo Liu Particle collision event generators are extremely useful, providing synthetic data quickly and to the user's specifications. At present, all such event generators function via underlying theory that provides rules by which particle multiplicities and momenta are generated. To remove theory dependence, the Empirically Trained Hadronic Event Regenerator (ETHER) at Jefferson Lab implements machine learning models to be trained on experimental data. The focus of this study is to improve the performance of the particle multiplicity generator and develop the implementation of a non-trivial conditional feature. An ensemble learning meta-algorithm is implemented to refine the model's learning ability. The base model is altered to accept a conditional label and is trained on continuous and discrete encoded labels. We find that the model's ability to learn rare events can be augmented through ensemble training, but it struggles to learn the shifts in the underlying data distribution necessary for the successful implementation of a conditional feature. Preliminary results suggest that many more training steps are required to implement a conditional feature in the generator model. [Preview Abstract] |
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HA.00077: The Upgraded Hall A BigBite Spectrometer Josh McMullen, Eric Fuchey, Douglas Higinbotham The recent 12 GeV upgrade to the Continuous Electron Beam Accelerator Facility (CEBAF) will allow for experiments in Thomas Jefferson National Accelerator Facility’s (JLAB) Hall A to probe deeper into the structure of the nucleon. The increased CEBAF beam energy expands the kinematic range in which high-precision measurements of the electro-magnetic form factor can be recorded. Crucial to these experiments is the use of Hall A’s BigBite Spectrometer to detect scattered elec- trons. While the BigBite detector package will be utilized in various configurations, an electromagnetic calorimeters will always serve as the primary trigger mechanism for these experiments. A detailed diagram of the trigger logic scheme will be shown along with brief summaries of the modules and timing information. The layout of the entire BigBite spectrometer package will also be shown along with descriptions of the various detectors. [Preview Abstract] |
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HA.00078: HF-Free Bipolar Pulsed Electropolishing of SRF Cavities Hannah Hu, Hui Tian, Olga Trofimova Surface roughness is one of the factors limiting the performance of superconducting radio frequency (SRF) accelerator cavities. Bipolar Pulsed Electropolishing (BPEP) is a surface processing treatment that uses anodic and cathodic pulses. BPEP uses a HF-free electrolyte, thus reducing the costs and hazards associated with HF while still yielding a comparable surface finish to that of traditional etching techniques. This project focuses on understanding how polishing parameters affect the etching processes of Nb as well as conducting initial testing on N$_2$ doped and Nb$_3$Sn samples. Nb samples were polished at varying anodic voltage and pulse repetition frequencies (PRF); N$_2$ doped and Nb$_3$Sn samples were repeatedly etched with 1 $\mu$m and 200 nm removal respectively. Before and after each treatment, samples were studied under an Atomic Force Microscope and Scanning Electron Microscope for surface roughness and morphology. For Nb, etch rate stays constant with anodic voltage and is directly proportional to PRF. For Nb$_3$Sn, BPEP selectively etches Nb, changing the chemical composition of Nb$_3$Sn. Understanding the effects of these polishing parameters enables us to apply BPEP more efficiently to single and multi-cell Nb, N$_2$ doped, and Nb$_3$Sn SRF cavities. [Preview Abstract] |
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HA.00079: Scattering in a Finite, Minkowski 1$+$1D Lattice Alexandru Sturzu, Raul Briceno, Maxwell Hansen There has been recent developments to allow lattice calculations in Minkowski space-time in order to determine real-time observables. These still require the use of finite volumes, where scattering observables may not be accessed directly. Furthermore, it is not obvious how one can recover infinite-volume scattering amplitudes from finite-volume Minkowski observables. To address this issue, we introduce a physical quantity that can be accessed from finite-volume Minkowski correlates and smoothly recovers the two-particle amplitude in the infinite volume limit. We test the convergence of this idea by considering a strongly interacting 1$+$1D toy model. [Preview Abstract] |
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HA.00080: A New Frequency Modulation Function for High Energy Compton Scattering Jeffrey McKaig, Balša Terzić, Geoffrey Krafft When a relativistic electron beam and a low energy laser pulse interact, narrow bandwidth back scattered radiation is produced through Compton Scattering. It has been shown that when the frequency of the laser pulse is modulated, a narrow bandwidth spectrum can be produced in the regime of high laser energies. However, this modulation function only corrects the spectrum for on axis scattering. Here a new frequency modulation function was developed to compensate for on and off axis scattering. This new function was derived using the method of stationary phase on the Fourier transform of the electron velocity in the x direction. In this treatment the scattering angle was kept arbitrary in order to account for off axis scattering. It is shown that this function does indeed recover the narrow bandwidth spectrum on and off axis. Unlike the previous modulation function, this function is shown to depend on the speed, and thus energy, of the electron beam. It is also shown that when electron energies are low, this modulation corrects the spectrum for all aperture placements. The findings of this study will allow for wider applications of the resulting spectrum as well as further development of the theoretical background of high energy Compton Scattering. [Preview Abstract] |
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HA.00081: Testing and Analyzing the BONuS12 RPTC at Jefferson Lab Raemaad Wright The BONuS12 (Barely Off-shell Neutron Structure) group intends to measure the fundamental structure of the neutron in the valence quark region. In order to accomplish this, electron beam would scatter off a deuteron target. To ensure scattering is off the neutron, slow, backward moving spectator protons would be tagged with a Radial Time Projection Chamber (RTPC). A gas panel has been built to distribute and control gas flow through the RTPC as well as a Drift Monitoring System (DMS). An RTPC is currently being tested using Helium-Carbon Dioxide (HeCO$_{\mathrm{2}})$ and is under high voltage, with cosmics and a radiologically controlled source (Sr-90) to see if a signal was generated on the oscilloscope. Once signals begin to show we will start to take data from the Data Acquisition System. This presentation will focus on the progress and results of this testing. [Preview Abstract] |
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HA.00082: Studies of the Gain of a Small-Pore Size Microchannel Plate Photomultiplier in High Magnetic Fields Alan Rowland Microchannel plate photomultipliers (MCP PMTs) are small devices that convert light into an electric signal. These devices have many applications, but most notably in physics they are used to readout Cherenkov detectors. In the current designs of the central detector of a future Electron Ion Collider, MCP PMTs will readout several Cherenkov detectors located in a magnetic field of \textasciitilde 1.5 T. Work has been done to see how the functionality of MCP PMTs is affected by high magnetic fields and our research furthers these studies. We studied a Planacon MCP PMT, which has a pore size of 10 \textmu m, inside a variable magnetic field. While one can simply determine the gain of the device outside of a field by means of fits to pulse height distributions, in high magnetic fields (\textgreater 1.5 T), where the signals become small, this method to determine the gain cannot be applied. Due to the linearity of the relationship between several variables that are proportional to the gain, we have developed a method to determine the gain even when the PMT signals are very small and the standard method is not useable. This helps to extend the range of settings for which the sensor can be evaluated and provides support for this sensor to be used in the EIC. [Preview Abstract] |
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HA.00083: Intrabeam Stripping of H- Ions in the JLEIC Ion Linac with PyORBIT Madeline Clyburn, Todd Satogata, Amy Sy Jefferson Lab is designing an electron-ion collider (JLEIC) to meet the experimental needs of the nuclear physics community. In JLEIC, a potential mechanism for beam loss is intrabeam stripping of the H- ions in the linear accelerator (linac). As the ions interact with each other, there is a chance that electrons will be stripped from the ions. This creates neutral particles that are unaffected by the electromagnetic fields and are thus lost. This project determined whether intrabeam stripping is a relevant form of beam loss for JLEIC. The pyORBIT code was modified to simulate the beam dynamics of the JLEIC linac. Then plots were created of relativistic velocity to determine the likelihood of intrabeam stripping. From these plots, the relativistic velocity values of the ion beam were found to be similar to values from previous studies on other linacs; however, the calculated average power of JLEIC is significantly lower than the powers of other linacs. Previous predictions have shown that intrabeam stripping is negligible below a certain average power value. Our value for average power was many orders of magnitude below this average power value and thus confirmed that intrabeam stripping of the H- ions will have negligible effects on the amount of beam loss in JLEIC ion linac. [Preview Abstract] |
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HA.00084: Quasielastic Scattering Simulation off Mean Field Nucleons Samuel Solomon, Jackson Pybus, Andrew Denniston, Efrain Segarra, Axel Schmidt, Or Hen Quasielastic (QE) electron-nucleus scattering is a powerful probe for nuclear structure, revealing a distinction between nucleons in mean-field orbitals and those in high-momentum, short-range correlated (SRC) states. Despite being difficult to calculate using ab initio methods, QE cross sections can be estimated from nuclear spectral functions using Plane-Wave Impulse Approximations (PWIA). Recently, a novel approach called Generalized Contact Formalism has been successful in describing the limiting case of QE scattering from a nucleon in an SRC pair. To extend this method, I developed software to simulate QE scattering from a mean field nucleon based on ab initio spectral function calculations. This allows for independent comparison of scattering events between SRC and mean field nucleons, which are difficult to distinguish experimentally. I plan on using these comparisons to test if the observed missing mass offset in SRC pair break-up reactions can be understood from conventional nuclear physics or is a signature of a previously unobserved 30 MeV force-carrying boson. [Preview Abstract] |
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HA.00085: Probing 2N-SRC via (e,e'N) Reactions off 3,4He (12C) Peninah Levine, Axel Schmidt, Reynier Cruz Torres, Erez Cohen, Or Hen, Eliezer Piasetzky Quasielastic electron-nucleus scattering suggests that 5--20{\%} of nucleons form short-range correlated (SRC) pairs with very small separation distances and very high relative momenta. Previously, coincidence measurements have provided the most complete picture of SRCs, but few coincidence measurements have been made on light nuclei. Here, we examine SRC-pair break-up from Jefferson Lab data from He-3 and He-4 for the first time. We study the effect of asymmetry and nuclear size on SRC pairing by probing (e,e'p) event ratios for $^{\mathrm{3}}$He/$^{\mathrm{4}}$He and $^{\mathrm{12}}$C/$^{\mathrm{4}}$He, respectively. The results of this study find scaling in (e,e'p) ratios as a function of Pmiss, which matches what we find using (e,e') events. The fact that both channels independently produce the same abundances indicates that inclusive measurements are correctly probing nucleon pair abundances in nuclei. This analysis paves the way for tests of np-dominance and other investigations of pairing in light nuclei. [Preview Abstract] |
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HA.00086: Simulations of Water-Cherenkov Events with a Sr90 Source for the Calibration of NuDot Experiment Junior Pena In searching for neutrinoless double-beta decay, it is crucial to understand backgrounds in liquid scintillator detectors for these rare events before the next generation of experiments at the kiloton-scale. With sufficient timing resolution to separate scintillation light from Cherenkov radiation, it is feasible to use directionality from Cherenkov light for identifying backgrounds like $^{8}$B solar neutrino scattering, which are otherwise irreducible. NuDot is a preliminary 1-ton experiment aiming to demonstrate this technique of separation and event reconstruction with 1 to 2 MeV beta particles. Simulations for NuDot are important for determining the calibration conditions, the amount of source positions needed, and the duration of runs at each position in order to obtain the precise timing calibration for Cherenkov separation. For calibrating, we use water-Cherenkov events from a Sr90 source, and the difficulty lies in simulating the model for how Cherenkov light is produced, how the PMTs behave, and how light propagates through the detector. To aid this issue we use RAT to simulate our experimental setup and calibration runs as closely as possible. A simulation of a timing calibration and how it compares to data collected when running in the same conditions will be shown. [Preview Abstract] |
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HA.00087: Data Acquisition and Triggering for the NuDot Experiment Manuel Morales In the search for neutrinoless double-beta decay, progress is being made towards kiloton-scale detectors with lower backgrounds. NuDot is a 1-ton liquid scintillator detector prototype designed to identify previously irreducible backgrounds like $^{8}$B solar neutrino scattering. Using Cherenkov light signals for path reconstruction of 1 to 2 MeV beta particles, NuDot aims to demonstrate this background reduction technique. NuDot’s DAQ system is complex in how it merges faster and slower signals. For high light-collection efficiency, 59 8” PMTs are split across 4 slow boards operating at 250 MS/s. To ensure fast timing, 152 2” PMTs are divided across 5 fast digitizer boards operating at 5 GS/s. When an event is detected by any of the 8" PMTs, a trigger is sent to all the boards housing 2" PMTs. Due to the limited waveform storage of the fast boards, triggers have to be sent in less than 200 ns to record the high-frequency data before it is overwritten. A variety of tests were performed to ensure this and other aspects of DAQ performance. Furthermore, all 9 boards are chained together in order to synchronize start time and utilize a shared clock timestamp. These processes facilitate the stitching together of event waveforms and further data analysis. [Preview Abstract] |
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HA.00088: The NuDot Calibration System Jesus Herrera To reach greater sensitivity, the search for neutrinoless double beta decay will require new techniques for rejecting background events. NuDot seeks to answer these problems by demonstrating Cherenkov/Scintillation separation in betas with energies of 1\hyph{--}2 MeV. This separation will be used to distinguish between single electron scatter events and double beta decay events, and provides ground to perform direction reconstruction of such events. Demonstrating the direction reconstruction of beta events in NuDot requires a calibration system capable of performing multi\hyph{--}directional movements independent of each other. This calibration system must be capable of controlling the height, azimuthal angle, and inclination angle of a Sr90 source and collimator. Utilizing three integrated stepper motors, independent motion can be achieved. With this setup, we can program such motors to point at any position on the sphere from any point along the sphere radius, and relay their exact positions to us. Given this capability, we can test our direction reconstruction and verify that the values from reconstruction match the position and orientation of the collimator on the calibration system. [Preview Abstract] |
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HA.00089: Transverse Distributions of the Pion Cloud in a Chiral Light Cone Perturbation Theory Model MacQuarrie Thomson, Ethan Purcell Purcell, Enrique Sanchez Because of the Heisenberg uncertainty principle, protons are allowed to briefly fluctuate into a pion and a nucleon or a pion and a delta. Our goal is to calculate the splitting of the proton into these separate particles while the proton is moving at relativistic speeds, where its spatial extent becomes nearly two-dimensional, a disk of pion cloud. We use a pion 2D momentum distribution function $f_\pi _N(y,t) $, derived from chiral light cone perturbation theory, in which $y$ is the fraction of proton momentum carried by the pion and the momentum transfer $t $ depends on $y$ and $k_\perp$, the transverse momentum of the pion. To find transverse momentum distributions we calculate $f_\pi _N $ as a function of $y$ and $k_\perp$ for a range of physically reasonable values of the form factors and coupling constants on which it depends. We then use a 2D Bessel transform of $f_\pi _N$ to calculate the transverse spatial probability distribution $\rho_\pi _N(y,b) $ with $b$ the transverse position coordinate. We compare our results to the expected spatial extent of the cloud, $\sim 1/m_\pi$, and to other theoretical transverse spatial distributions. [Preview Abstract] |
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HA.00090: Transverse Distributions of the Strange Cloud of the Proton Ethan Purcell, Enrique Sanchez, MacQuarrie Thomson Due to the Heisenberg uncertainty principle, a proton can generate a cloud of strange particles as it splits into a strange meson/baryon pair: a $K$ or $K^*$ meson and a $\Lambda$ or $\Sigma$ baryon. At relativistic speeds the proton is contracted into a disk transverse to its momentum. Our goal is to calculate the transverse momentum distributions and determine the transverse spatial distributions of the strange mesons. We use a light cone model for the two-body wave function $\psi(y,\ k_\perp)$ that describes the probability that a proton will split into a meson/baryon pair in which the meson has longitudinal momentum fraction $y$ and transverse momentum $k_\perp$. We analytically integrate $\psi(y,\ k_\perp)$ to determine $f(y)$, the probability of the meson-baryon fluctuation for a given $y$. We numerically integrate $f(y)$ and compare to total fluctuation probabilities, and use this to normalize our distributions. $\psi(y,\ k_\perp)$ depends upon a parameter $\alpha$ which describes the shape of the fluctuation function. We study the dependence of the transverse momentum distributions on $\alpha$. We then use a Bessel function transformation of $\psi(y,\ k_\perp)$ to determine the transverse spatial extent of the kaon cloud, and compare it to the expected scale of $1/m_K$. [Preview Abstract] |
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HA.00091: Light Cone Model of the Transverse Distributions of the Pion Cloud Enrique Sanchez, MacQuarrie Thomson, Ethan Purcell The Heisenberg time-energy uncertainty principle allows a proton to briefly fluctuate into a $\pi N$ or a $\pi \Delta$ state. This fluctuation phenomenon creates a cloud of pions, which we investigate for protons moving at relativistic speeds. We describe the pion cloud in a Fock state expansion, in which we use two-body Gaussian wave functions in a Light Cone model to determine the probabilities of each proton fluctuation. The wave functions $\Psi_\pi_B (y,k_\perp)$, with $B=N, \Delta$, depend on $y$, the pion momentum fraction, and $k_\perp_$, the transverse momentum, in which we are interested. To normalize these wave functions we first calculated the probability that the proton will fluctuate into a $\pi N$ or $\pi \Delta$ state by integration over $k_\perp_$ and $y$, and set our results equal to values determined by experiment. Our normalization constants depended on a parameter $\alpha$ in the wave functions, related to the width of the distribution in momentum space. We made 3D plots to study the dependence on $y$ of the transverse distributions in $k_\perp$. We then used a 2D Bessel transform to determine the transverse spatial distributions of the pions, which we expect to be $\sim 1/m_\pi}$. We compare our results to other theoretical calculations. [Preview Abstract] |
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HA.00092: Time-Reversal-Violating Interactions in the Neutron Deuteron System Anna David, Jared Vanasse Time reversal violating interactions within the Standard Model occurs between quarks and at low energies manifests itself in nucleon-nucleon interactions. Time reversal and parity violating nucleon-nucleon interactions, at low energies $E |
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HA.00093: Collinearity criteria for transverse momentum dependent distributions in SIDIS Scott Dolan, Mason Albright, Leonard Gamberg, Wally Melnitchouk, Daniel Pitonyak, Alexey Prokudin, Nobuo Sato, Zachary Scalyer We present the impact of data selection on the determination of nonperturbative transverse momentum dependence in semi-inclusive deep-inelastic scattering (SIDIS). In particular, we implement for the first time the recently introduced collinearity criteria [1] that allow selection of data predominantly in the current fragmentation region, and apply this framework to pion and kaon multiplicity data from HERMES. We use a simple analytical approximation for the solutions of the TMD evolution equations that is valid in the nonperturbative region [2], and extract the transverse momentum dependence of TMDs and the flavor dependence of their widths. We compare the resulting unpolarized TMD PDFs with previous extractions, and discuss the potential impact of the data selection criteria for future experiments. We summarize our findings and discuss the impact of this analysis for ongoing and future experiments of SIDIS. [1] ~M. Boglione, J. Collins, L. Gamberg, J. O. Gonzalez-Hernandez T. C. Rogers, N. Sato, Phys.Lett.B766,245(2017), [2] J.C Collins and T. R. Rogers, Phys. Rev. D 91, 074020 (2015). [Preview Abstract] |
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HA.00094: Improvements in Fiber Harp Signal Integrity in the Muon g-2 Experiment Jade Meurer, Frederick Gray The Muon $g$-2 experiment at Fermi National Accelerator Laboratory will test fundamental symmetries of the Standard Model by measuring the anomalous magnetic moment of the muon with improved precision. We measure motion of the beam profile through a system of ``fiber harps,'' consisting of scintillating fibers and Silicon Photomultipliers (SiPMs). Signals from previous versions of the SiPM amplifier circuits show long time constants in the recovery to the baseline voltage, resulting in a need for precise baseline corrections and/or new electronics. We attempt to improve the analysis of previous data by applying mathematical deconvolution methods. We also develop new DC coupled amplifiers to fix the baseline shift introduced by AC coupling for future data collection. This poster will present the success of these methods and future improvements.~ [Preview Abstract] |
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HA.00095: A Jet Shape Study with the STAR Experiment Thomas Gosart In relativistic heavy ion physics, jets are a collection of particles that are emitted from hard scattered partons. They are known to interact strongly within quark-gluon plasma (QGP) produced in heavy ion collisions, which is known as jet quenching. It has been observed at the LHC that jets' energy deposition and radiation patterns change when they interact with QGP compared to their vacuum baseline. Jet shape is an observable that is sensitive to the changes within a jet and its lateral energy distribution. In this study, we utilize data collected by the STAR experiment at RHIC to compare the evolution of the jet shape observable in proton+proton and $\sqrt{s_{NN}} = 200$ GeV Au+Au collisions. Such measurements allow us to have a better understanding of the jet quenching phenomenon in heavy ion collisions at RHIC. [Preview Abstract] |
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HA.00096: Control Improvements on the UCN$\tau$ Magnetic Mapper Ryan Colon The UCN$\tau$ experiment utilizes a 670-liter magnetic array designed for the purpose of trapping ultracold neutrons (UCN) with minimal sources of loss. The array uses over 5000 NdFeB magnets to achieve this purpose. Understanding the magnetic field generated by these magnets is key to the experiment, and so it is necessary to have a practical method of mapping the magnetic fields in the trap. This information is useful for ensuring the magnetic field is large enough everywhere to prevent UCNs from escaping and provides empirical inputs into spin dynamics simulations of the experiment. To efficiently collect the magnetic field information, a magnetic field mapping robotic arm was manufactured and implemented, and the efficiency of the arm continues to be improved upon. Control code was improved to allow for the automatic handling of critical errors during mapping runs. Specifically, code allowing for the arm to try and re-find a missed surface point and skip points that it fails to find was implemented; Additionally, code that allows the arm to continue an aborted mapping run with minimal user input after critical errors was developed. The control code additions and their effects on the running of the arm, as well as future control code improvements will be presented. [Preview Abstract] |
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HA.00097: Development of a sCMOS Position-Sensitive UCN Detector Darsh Dinger, Adam Holley Position-Sensitive Detection (PSD) of particles on a two-dimensional detection plane can be useful in experiments that require characterization of free-moving particles. PSD can aid in the study of systematic effects such as depolarization and phase space evolution in trapping experiments such as the ultracold neutron (UCN) free neutron lifetime experiment UCN$\tau$. PSD is demonstrated using a relatively inexpensive “scientific” complementary-symmetry metal-oxide-semiconductor (sCMOS) camera from PCO to image an Ag enriched ZnS scintillator coated in $^{10}$B from a distance of 1.2 meters away. This scintillator was excited using an $^{241}$Am source which emits alpha particles at 5.48 MeV. The optical design of this PSD system will be discussed, along with details of signal characterization. [Preview Abstract] |
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HA.00098: Monte Carlo study of $\Upsilon(1S)$ production in jets in the forward region Yijin Guo The Large Hadron Collider beauty (LHCb) experiment primarily studies the production and decay of beauty and charm hadrons. Different from ATLAS and CMS, which mainly cover the mid-rapidity region, the LHCb detector uniquely covers the forward region $(2<\eta<5)$ with precise tracking and particle identification capabilities. A recent study of $J/\psi$ production in jets presents the first measurement of transverse momentum fraction, $z(J/\psi) = p_{T}(J/\psi)/p_{T}(jet)$, in the forward region. Despite the consistency between theoretical predictions and measurements of $z(J/\psi)$ from b-hadron decays, a disagreement is found for prompt $J/\psi$ production. It inspires parallel studies of the production of prompt upsilons in jets, to compare charmonium in jets to heavier bottomonium particles. Here, an analysis of ground state upsilons $(\Upsilon(1S))$ in jets in the forward region with Monte Carlo events generated at a center-of-mass energy of 8 TeV will be presented. The energy and transverse momentum $(p_{T})$ distributions for inclusive $\Upsilon(1S)$ will be shown, and the calculations including $z(\Upsilon)$, longitudinal momentum fraction $(z)$, radial distance $(r)$ and momentum transverse $(j_{T})$ to jet axis will be performed for $\Upsilon(1S)$ in jets. [Preview Abstract] |
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HA.00099: Clustering of Mini-jets in High-Energy Proton$+$Proton Collisions Nanxi Yao The jets, narrow bundles of hadrons, manifest the properties of quarks and gluons in high-energy p$+$p and heavy-ion collisions. Observation of jets helps to investigate the quark gluon plasma (QGP) created in such collisions, and plays a significant role in understanding Quantum Chromodynamics (QCD). Although jets are usually distinguished with high-momentum hadrons, mini-jets and mini-dijets will clarify multiple parton interactions in the low transverse-momentum region. In this poster, an algorithm of finding mini-jets is presented, based on K-means clustering method [1]. We partition particles from p$+$p collisions at 200 GeV simulated by PYTHIA8.1 into clusters by minimizing a potential of the system, and determine the center of the clusters. To further evaluate the cluster-finding algorithm, we analyze differential correlations between cluster centers in the pseudorapidity and azimuthal angle space. This study will pave the road for future application in heavy-ion collisions. [1] C. Wong, L. Wen, G. Wang and H. Z. Huang: ``On the Clustering Properties of Mini-Jet and Mini-Dijet in High-Energy pp Collisions'', 2018; [http://arxiv.org/abs/1801.00759 arXiv:1801.00759]. [Preview Abstract] |
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HA.00100: Photon Reconstruction and Identification in sPHENIX Francesco Vassalli The super Pioneering High Energy Nuclear Interaction eXperiment (sPHENIX) at the Relativistic Heavy Ion Collider (RHIC) will perform high precision measurements of photon-jet production to study the strongly coupled quark-gluon plasma. Comparison of the color neutral photon with the strongly-interacting jet provides a natural control-experiment channel. In sPHENIX Photon kinematics are reconstructed using calorimeter data. To obtain a high purity sample of prompt photons the hadronic background, especially $\pi^0$ decay, must be reduced. This can be done by analyzing the calorimeter cluster shape. The methods of event reconstruction for sPHENIX are currently being developed and tested in simulation. The results will serve as a benchmark for the capabilities of the detector. Furthermore, the photon identification efficiency can be increased through converted photon recovery. Photon conversion recovery is performed by analyzing electron, positron track pairs. Photon conversion recovery can also be used to make material maps of the inner detector in simulation and data. Comparing these maps allows for detailed in situ verification of detector geometry. This presents sPHENIX's ability to reconstruct and identify photons using GEANT4 simulation. [Preview Abstract] |
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HA.00101: ZDC prototypes for test beam measurements at CERN and FNAL Tiansu Zhang The High Luminosity upgrade of the Large Hadron Collider at CERN places significant demands on the radiation hardness of the Zero-Degree Calorimeter (ZDC) of the ATLAS experiment. This detector plays a key role in the heavy ion physics program, in particular in the measurement of the impact parameter and of the number of spectators nucleons in the collision. The Nuclear Physics Laboratory at the University of Illinois (NPL) collaborates on the development of a radiation-hard ZDC for ATLAS. As part of this upgrade effort, prototype hadronic and electromagnetic detector modules along with a single layered reaction plane detector (RPD) have been built. In November 2018, a dedicated beam-test has been performed at the H4 beam-line at CERN. Two hadronic detector modules have been tested, together with an RPD prototype. The detector was illuminated with both heavy ion and fragment beams, to study its properties. In my contribution, I will discuss the 2018 test-beam effort, with particular attention to the alignment of the setup, its simulation in Geant4 and the data analysis. [Preview Abstract] |
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HA.00102: Development of a Fused Silica Polishing Method Andi Mankolli The Large Hadron Collider at CERN~is being upgraded for~high luminosity~operations. Protons and heavy ions in the accelerator will collide with unprecedented rates, giving rise to an extremely high-radiation environment.~Operating under this high-radiation exposure will be a significant challenge for detector instrumentation, especially for detectors positioned near the beam at small scattering angles. One of these detectors is~the Zero Degree Calorimeter (ZDC) of the ATLAS experiment. The ZDC is located inside the LHC tunnel and plays a key-role in determining centrality and number of spectators in heavy ion collisions. The~Nuclear Physics Laboratory (NPL) at the University of Illinois collaborates on the development of~a radiation-hard~ZDC for the~ATLAS detector. The ZDC will consist of an electromagnetic module, to detect high energy photons and electrons, followed by three hadronic modules, detecting spectator neutrons from nuclear collisions. The ZDC will be equiped with~a Reaction-Plane Detector (RPD), to determine the shower profile~and the collision geometry. Both hadronic and electromagnetic modules will be~tungsten sampling~calorimeters. The active Cherenkov radiator consists of~radiation-hard~fused silica~rods which were developed for LHC luminosity monitors. We present a polishing method for the ends of the rods that was developed to achieve high and uniform light transmission.~Prototype detectors were designed,~constructed and~tested at the CERN SPS in November 2018 and at the Fermilab Test Beam Facility in July 2019.~The poster will discuss test beam results for the ZDC prototype performance and present comparisons to MC simulations. [Preview Abstract] |
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HA.00103: Characterizations of UV-sensitive large area SiPMs and its readout for nEXO JiaZhao Lin, Jonathan Echevers, Liang Yang Silicon Photomultiplier (SiPM) has emerged as a new light sensor for noble liquid detectors. The next-generation Enriched Xenon Observatory (nEXO), a proposed experiment to search for neutrino-less double beta decay, will use SiPMs for detecting Xenon scintillation light. Detailed analysis on the performances of SiPMs under cryogenic experimental conditions is required for future nEXO experiment. In the poster, we will describe the experimental setups and present the results of characterization of SiPMs from FBK. In particular, we present the large-area readout analysis for the resolution, gain and dark noise rate of SiPM under cryogenic condition. [Preview Abstract] |
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HA.00104: Single Particle Simulation Studies of a Proposed Forward Calorimeter for the sPHENIX Experiment Yuxi Xie The sPHENIX experiment is designed to study the quark-gluon plasma, a state of hot nuclear matter created in heavy-ion collisions. A forward upgrade including tracking and calorimetry is proposed for sPHENIX to extend the range for cold nuclear matter measurements, in particular with direct photon and quarkonia, which can be used to constrain the gluon nuclear parton distribution function. The implementation of the plans on re-using the existing E864 hadronic calorimeter modules for the forward electromagnetic calorimeter requires a non-uniform tower structure. The calorimeter performance was studied with single-photon and single $\pi^0$ simulations, showing that the energy responses over pseudorapidity and azimuthal angle in the forward EMCal are uniform despite the nonuniformity of the tower size. Results on the fraction of $\pi^0$s that can be successfully reconstructed as a function of momentum will be presented. The single-particle simulation studies indicate that the proposed forward electromagnetic calorimeter upgrade has promising potential for use in extending the physics program of sPHENIX. Further studies involving full-event simulations will be performed to study the detector performance for distinguishing direct photons from photons decayed from $\pi^0$s. [Preview Abstract] |
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HA.00105: Determining analysis efficiency for Project 8's neutrino mass studies Sierra Wilde The Project 8 experiment is developing a way to study neutrino mass called Cyclotron Radiation Emission Spectroscopy (CRES). In CRES, an electron's energy is measured by observing the cyclotron radiation emitted by the electron as it accelerates in a magnetic field; because of a special relativistic effect, this frequency depends on the electron's kinetic energy. A radiofrequency detection system collects, measures, and digitizes information about the radiation, and Project 8 analysis software processes the data to distinguish electron signals from noise. However, many electron signals are comparable in power to the noise, which can lead to missed signals and errors in cyclotron frequency reconstruction. This work aims to quantify the systematic effects of variations in signal properties on measured cyclotron frequencies. We use a Project 8 software package to create simulated electron signals and noise. We vary parameters of the simulated signals, and then measure how these variations affect the analysis efficiency in finding signals and its accuracy in determining their frequency. These calibrations will make it possible to quantify uncertainties in Project 8's ongoing experimental observation of the spectrum of electrons emitted in the beta decay of tritium. [Preview Abstract] |
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HA.00106: An Internal Scanning Cryostat for High Purity Germanium Detectors Tim Mathew LEGEND is a next-generation search for neutrinoless double-beta decay ($0\nu\beta\beta$) in $^{76}$Ge incorporating successful technologies from current experiments including the \textsc{Majorana Demonstrator} and GERDA. The $^{76}$Ge high purity germanium (HPGe) detectors use a P-type Point Contact (PPC) geometry. The passivated surfaces on these PPCs make the detectors susceptible to surface backgrounds, such as alpha and beta particles. This can contaminate the $0\nu\beta\beta$ region of interest at 2039 keV. The Collimated Alphas, Gammas, and Electrons (CAGE) test stand is an internal-source scanning cryostat, using vacuum-side motors to control the position of various radioactive sources above an HPGe detector. CAGE is currently taking data at the University of Washington to understand and characterize detector response to surface background events. The data from CAGE will be essential in identifying characteristics of surface event pulse shapes that can be used for event rejection in both current-generation experiments and LEGEND. This poster will present the current status of the CAGE test stand, as well as preliminary data. [Preview Abstract] |
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HA.00107: Event selection in electron scattering from an unpolarized deuterium target. Xiaodi Hu, Matthew Heyrich, Gerard Gilfoyle We are using Jefferson Lab's 11-GeV electron beam incident on a deuterium target and the CLAS12 detector to measure the electromagnetic form factor of the neutron. We developed and tested code to extract kinematic quantities for quasielastic(QE) event selection. A full simulation chain has been developed and is managed by shell and perl scripts on the Richmond Computing Cluster. Quasi-elastic events are generated with QUEEG and inelastic ones with Pythia. Both sets go through gemc, a CLAS12-standard, physics-based Monte Carlo built on geant4. The simulated events are reconstructed with the CLAS12 Common Tools. We wrote the post-reconstruction analysis code in Apache Groovy, a JAVA-like scripting language. To select electrons we apply fiducial cuts to define the electromagnetic calorimeter (EC) active volume and constrain the sampling fraction (ratio of electron energy deposited in the EC to measured electron momentum). We isolated QE events from inelastic background using cuts on $\theta_{pq}$ (angle between 3-momentum transfer and the nucleon), and the hermiticity (number of final-state particles). Initial results on extracting the QE component are consistent with the experimental specifications. [Preview Abstract] |
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HA.00108: Calculations of Transverse Energy from Single Particle Spectra Measured in Relativistic Heavy Ion Collisions Tanner Mengel, Benjamin Smith, Biswas Sharma, Nathan Webb, Soren Sorensen, Christine Nattrass During relativistic collisions of heavy nuclei, such as gold, a hot dense medium know as Quark Gluon Plasma (QGP) is formed. As a consequence of such collisions, particles are ejected transverse to the beam axis. The transverse momentum distributions, measured by the STAR and PHENIX experiments at the Relativistic Heavy Ion Collider (RHIC) in Brookhaven National Laboratory, are used to calculate the transverse energy of ejected particles. These momentum distributions correspond to nine centralities for eight identified particles, $\pi^{\pm}, K^{\pm}, \Lambda, \bar{\Lambda}, \it{p}$, and $\bar{p}$, at eight different center-of-mass energies per nucleon. Comparing the estimated transverse energy shows the systematic biases of the different methods used to measure ejected particles during heavy ion collisions. We describe methods used in calculating the transverse energy contributions from each of the identified particles in published momentum spectra, as well as assumptions made for calculating energy contributions from unmeasured particles, such as, $\eta, n, \pi^{0}$ and $K^{0}_{s}$. [Preview Abstract] |
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HA.00109: Heavy Ion Collision Analyses Using RIVET Christal Martin, Christine Nattrass When heavy ions collide at ultra-relativistic speeds, a hot, dense state of nuclear matter known as Quark-Gluon Plasma (QGP) is formed. To study the properties of the QGP, data are collected from heavy ion collisions at the Large Hadron Collider (LHC) in Switzerland and the Relativistic Heavy Ion Collider (RHIC) in New York. Experimental analyses using this collected data can be studied using a Monte Carlo (MC) validation software called Robust Independent Validation of Experiment and Theory (RIVET) to make comparisons between experimental data and MC models. Heavy ion analyses are being developed for use by the JETSCAPE collaboration. We discuss procedures to create heavy ion collision analyses using RIVET. We also demonstrate how to incorporate these procedures and analyses into an academic research course. [Preview Abstract] |
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HA.00110: Determining $\pi^0$ $A_{LL}$ from STAR 2012 Endcap Calorimeter Data Claire Kovarik The Solenoidal Tracker at RHIC (STAR) located at Brookhaven National Laboratory in New York uses longitudinally polarized proton-proton collisions to determine the gluon contribution to the spin of the proton. One analysis of the 2012 data set, at a proton-proton center of mass energy of 510 GeV, studies the production of neutral pions ($\pi^0$) which immediately ($\sim$ 10$^{-16}$s) decay into two photons. The neutral pion asymmetry, $A_{LL}$, can be determined through data collected by the Endcap Electromagnetic Calorimeter (EEMC). The EEMC, positioned in an intermediate pseudorapidity range of 1 $<$ $\eta$ $<$ 2, is able to measure the energy and position of each photon’s electromagnetic shower. By using this information as well as the angle between the photons, the two-photon invariant mass can be reconstructed. The invariant mass spectra are fitted using a skewed Gaussian plus a background function to determine the total number of $\pi^0$s present. The $\pi^0$ asymmetry is calculated from the number of $\pi^0$s in collisions with different polarization directions of the colliding proton beams. The status of the measurement of $A_{LL}$ of the $\pi^0$s as a function of the transverse momentum, $p_{T}$ , of the $\pi^0$ will be presented. [Preview Abstract] |
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HA.00111: Automation and Machine-Learning can help you do more physics sooner Spencer Shank, William Lillis Detector calibration is a task that is critical, mundane, and time consuming. As detector arrays have grown in scale, the tasks required have grown as well. For experiments with the MoNA/LISA neutron detectors it is critical to calibrate the arrays' 576 timing and energy response in order to extract accurate physics data. We will report on methods leveraging automation and machine intelligence to determine calibration parameters, and identify detector elements that require additional attention and/or adjustment from experimenters. We will report on methods using a large number of cosmic-ray tracks to determine relative time offsets of the 288 detector bars, based on a truncated travelling salesman-like approach. Additionally, two methods of determining positions will be explored, one based on the ratio of the scintillation light reaching the two ends of a detector bar, and one using the time difference between the ends. These two methods will be compared, showing that light difference can be used as backup to time difference in some cases, and that specific types of two-neutron events can be distinguished using these parameters and machine learning. These methods can reduce the time taken to calibrate and help one move from calibrations to physics sooner. [Preview Abstract] |
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HA.00112: Determining Scintillator Nonlinearity using the Wide Angle Compton Coincidence Technique Anna Beggs, Elizabeth George, Paul Voytas At some level, scintillator materials have an energy response that can be nonlinear. The Wide Angle Compton Coincidence (WACC) technique provides some advantages to finding the nonlinearity of a detector by using Compton scattering from this detector into another detector known to be linear, in this case a High Purity Germanium (HPGe) detector. The detectors are in a close geometry and so the Compton scattering that happens in the tested detector over many angles gives an energy response over a range of energies. From the known gamma ray energy and the HPGe photon energy detected, the analysis of a 2D histogram of the scattering detector response vs. the HPGe response provides a means of measuring the scattering detector's nonlinearity. I will describe our implementation of the WACC technique to measure the nonlinearity of scintillators used for a precision measurement of the $^{20}$F beta spectrum shape as a search for physics beyond the standard model. [Preview Abstract] |
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HA.00113: An Empirical Model of Electronegative Impurities for nEXO Samuel Borden Neutrinoless double beta-decay is a hypothesized radioactive decay, that if observed, would prove that the neutrino is a Majorana particle. nEXO is a future tonne-scale liquid xenon (LXe) time projection chamber (TPC) designed to search for the neutrinoless double-beta decay of Xe-136. Future tonne-scale LXe TPCs such as nEXO will require electrons to be drifted over meter long distances while minimizing loss of charge during drift due to the capture of electrons by electronegative impurities within the LXe. We will present an empirical model for predicting the level of electronegative impurities in nEXO, based on measurements of outgassing of atmospheric gases from plastics and other detector materials. The model is validated using electron lifetime measurements from EXO-200 and dedicated small-scale setups. [Preview Abstract] |
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HA.00114: Optimizing the Region of Interest in the KATRIN detector system Victoria Kubyshko The KATRIN experiment is currently obtaining data to determine the effective electron neutrino mass with a sensitivity of 0.2 eV/c$^{\mathrm{2}}$ by precision electron spectroscopy near the endpoint of the $\beta $-decay of tritium. The neutrino mass is determined by an integrated spectrum which currently uses a fixed wide region of interest (ROI) cut from the detector's energy spectrum, from 14keV to 32 keV. We expect an energy peak around 28keV, accounting for a 10keV shift from the endpoint energy of 18.6keV. This method discards data from some noisy pixels and shadowed pixels. The goals of this project were to determine the resulting sensitivity of the spectrum when changing the ROI, recommend a method to obtain the best suited ROI, and salvage the data from unused pixels using data from the first tritium runs. Some factors we have considered are background noise, shifting of the peak due to changing potentials, and nonuniformities among pixels. This resulted in the comparison of various ROI cuts to the one currently used. [Preview Abstract] |
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HA.00115: Software Updates for the Main Detector Controls Webpage at the STAR Experiment at Brookhaven National Laboratory Emma Dufresne STAR (Solenoidal Tracker at RHIC), the high-energy physics experiment at Brookhaven National Laboratory, analyzes collisions of heavy ions traveling at relativistic speeds using various detectors. For safety reasons, remote computers are programmed to retrieve data from these detectors. A controls system is set in place to manage the various computers that allow STAR to function. STAR's control system uses EPICS (Experimental Physics and Industrial Control System), a set of open-source software tools that enable communication with the computers. The largest part of the controls system involves the operation of power supplies and monitoring their voltage values. Detector operators and the shift leader can monitor safety information about the detectors from a single webpage. Information about water and gas alarms, operating status of the sub-detectors, and environmental conditions are seen at a glance. The detector controls framework is being gradually updated to include PC-based rather than embedded computers and to incorporate PyEpics, an interface that allows EPICS to interact with the Python Programming language. These changes will allow for easier maintenance and updates in the future. This project was to re-write the code that gathers and fills the main detector controls webpage with information, remove outdated values and eliminate the need for frequent rebooting. In alignment with the overall trend for detector controls, it was written using PyEpics and HTML formatting. This new code was successfully implemented before the end of the 2019 run. [Preview Abstract] |
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HA.00116: Determining the Reconstruction Efficiency \\ of $\Lambda^0$ Hyperons in CLAS12 at Jefferson Lab Matthew McEneaney, Anselm Vossen $\Lambda^0$ hyperons can be produced from hadronization of a struck quark in SIDIS processes. This is of interest as their polarization may be inferred from their self-analyzing weak decay. Thus, such polarized probes allow one to analyze the polarization of quarks in the proton and test fundamental aspects of QCD. The CLAS12 experiment at Jefferson Lab uses an $11$ GeV electron beam incident on a polarized or unpolarized target to study the behavior of the strong force within the proton. In this study, we generated SIDIS events using a Lund Monte Carlo and simulated the response of the CLAS12 detector using GEANT4 with different toroidal magnet field strengths and configurations (either inbending or outbending). We then processed events using the CLAS12 reconstruction framework to find the optimal configuration and maximize our reconstruction efficiency from the $\Lambda^0\rightarrow\pi^-+p^+$ decay channel. For $\Lambda^0$ hyperons coming from a struck quark ($x_{Feynman} > 0$), we obtained our best reconstruction efficiency in the outbending toroidal configuration. We will present the results of this study along with the implications on the statistical precision of a potential measurement of $\Lambda^0$ polarization using the data to be collected by CLAS12. [Preview Abstract] |
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HA.00117: Finding a Material with a Low Energy Threshold for Charged--Current Neutrino Interactions Thomas Richards, Kate Scholberg We calculated the thresholds for charged--current electron neutrino and antineutrino interactions for most of the stable isotopes. Looking at the isotopes with the lowest thresholds, we found that tantalum--181 ($^{181}$Ta) and gadolinium--160 ($^{160}$Gd) are reasonable candidates for low--threshold neutrino detectors, with thresholds at $0.188$ MeV and $0.105$ MeV respectively. These materials are both metals, have relatively high natural abundance, and are not frequently found in conjunction with radioactive substances, making them potentially viable for this task. Using the SNOwGLoBES software library, we computed estimated cross sections and event rates for supernova fluxes in these two materials. [Preview Abstract] |
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HA.00118: Measurements of the $^{124}$Sn($\gamma$,n) and $^{169}$Tm($\gamma$,n) cross sections at E$_\gamma$ = 13 MeV Kaylisa Wolsey, Sean Finch, F. Krishichayan, Jack Silano, Werner Tornow, Anton Tonchev, Innocent Txorse Nuclear data for photo-nuclear reactions is scarce. By using the activation technique, ($\gamma$,n) cross sections can be measured to a high precision. $^{169}$Tm(n,2n) is a common neutron monitor reaction, but there is no available data on its photo-nuclear counterpart, the $^{169}$($\gamma$,n) reaction. Measurement of this reaction would allow use of thulium as a standard $\gamma$-ray monitor. The samples in this experiment were irradiated by monoenergetic $\gamma$-rays provided by the High Intensity $\gamma$-ray Source (HI$\gamma$S) located at Duke University. The resultant activity was quantified using $\gamma$-ray spectroscopy with high purity germanium detectors. The data confirmed the literature half-lives of $^{196}$Au, $^{123m}$Sn, and $^{169}$Tm as 6.16 d, 40.1 m, and 93.1 d, respectively. The first successful cross-section measurements of $^{124}$Sn($\gamma$,n)$^{123m}$Sn and $^{169}$Tm($\gamma$,n)$^{168}$Tm reactions were performed. [Preview Abstract] |
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HA.00119: Scrubbing system Supporting tritium gas target for research at HI\textunderscore \textunderscore S Talisi Meyer, Collin Malone, Calvin Howell Tritium, a radioactive isotope of hydrogen, will be the basis of study of P-02-13 at HIGS. This study will use a tritium gas target to obtain cross-section measurements of two- and three-body photodisintegration of the triton in order to further understand nuclear structure and reactions, specifically three nucleon interactions (3NI). Tritium scrubber systems are necessary in order to safely handle the tritium inventory. These systems use a Copper-Zinc catalyst to convert elemental T$_{\mathrm{2}}$ into T$_{\mathrm{2}}$O or HTO, allowing the tritiated water to be collected in a molecular sieve bed and safely disposed of. Reactions catalyzed by the CuZn bed were examined using a Residual Gas Analyzer at temperatures ranging from 23\textdegree C to 190\textdegree C. Isotope concentrations and compositions of the various gas streams that will flow through the scrubbing system during normal operation were monitored over time to characterize the catalyst's behavior. Primary gases include Helium (\textasciitilde 5 LPM), 1{\%} Oxygen in Helium (\textasciitilde 5 LPM), Hydrogen (50-100 sccm), and H$_{\mathrm{2}}$O formed from the catalytic reaction. Through this research, the use of a CuZn bed as a catalyst in this scrubbing system was verified and found to work optimally at higher temperatures. [Preview Abstract] |
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HA.00120: Sensitivity Study to Identify Important Nuclear Reactions in X-ray Burst Nucleosynthesis Brittney Contreras When neutron stars (NS) in a low mass x-ray binary system collect matter from their H or He rich companion star, nuclear burning can occur on the NS's surface. If a critical accretion rate is reached, nuclear reactions can runaway, resulting in X-Ray Bursts (XRBs). By studying the sensitivity of XRB models to different nuclear reactions, we can help identify which are key in the burst process. The stellar model used for this study was of an XRB in Modules for Experiments with Stellar Astrophysics (MESA). Python scripts were made to analyze the output data and compare it to the baseline model. Those with the greatest change identify key reactions to XRB nucleosynthesis. Preliminary results already indicate five reactions of significance. Additional dominant reactions will be identified with further runs. While in its early stage, the study has emphasized reactions that majorly affect XRB properties. Future work will expand on these current methods to calculate the primary metric ``integrated burst variation'' and compare it to baseline. As stellar modeling capabilities have improved, this work will be a crucial contribution to sensitivity studies performed in the past. [Preview Abstract] |
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HA.00121: Development of Pelletron Accelerator for High Precision Calibration of Silicon Detectors Emmanuel Aneke, Clay Fogleman, Albert Young Neutron beta decay (NBD) is the decay of a neutron into a proton by the emission of an electron and electron antineutrino. When we measure the emitted electron, it can have any energy from 0 keV to 783 keV. The emitted electron energies are difficult to precisely measure because of bremsstrahlung, the emission of electromagnetic radiation produced by the deceleration of an electron hitting an atomic nucleus. For the next generation of beta decay measurements, the precision of current bremsstrahlung simulations are not sufficiently precise, motivating direct measurement of the bremsstrahlung loss to calibrate NBD electron energy measurements. We are developing a pulsed and tunable Pelletron accelerator (mostly from spare parts) to provide these measurements. The development of our Pelletron system is the first concern before any bremsstrahlung measurements are made. Our project is to improve the performance of an N$_2$ purge and implement a suppressor electrode to reduce arcing, understand possible sources of coronal discharge loss, make a first detection of the electron beam, and start to develop a test beamline. These first steps were successful, greatly reducing charge loss and arcing, and confirming the production of over 200 keV electron beams. [Preview Abstract] |
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HA.00122: Tagging $c\bar{c}$ events via hadronic decay modes of $J/\psi$ at ATLAS Sergi Castells, Nicolo de Groot Searches for $c\bar{c}$ from Higgs/Z decays have been done exclusively for the ground $J/\psi$ state for leptonic decay modes while we aim to tag excited $c\bar{c}$ states via hadronic decay modes. The study of $c\bar{c}$ is relevant to Higgs coupling with the charm quark. Excited energy states such as $\psi(2S)$ and $\chi_{c_0,c_1,c_2}$ are of interest as we can follow their decays into $J/\psi\,\gamma$. The production of excited states of $c\bar{c}$ is via the standard Higgs/Z production chain $gg \rightarrow H$ which produces $c\bar{c}$ via the $H \rightarrow c\bar{c}\,\gamma$ process. The purpose of creating this tagging algorithm is to apply it to ATLAS data. The tagging is done using machine learning. Training data for the machine learning algorithm comes from Monte Carlo simulations of particle decays and simulations of interactions in ATLAS. Other Monte Carlo simulations are being tested to verify the stability of the algorithm. The accuracy for the fully-connected neural network trained on $J/\psi$, $\psi(2S)$, and quark/gluon background is 93%. This novel approach to $c\bar{c}$ tagging resulted in a production-ready tagger. Further study is being done into using a convolution neural network for $c\bar{c}$ tagging. [Preview Abstract] |
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HA.00123: The CLAS12 Forward Tagger Calorimeter Robert Behary, Fatiha Benmokhtar, Raffaella De Vita, Marco Battaglieri Lead tungstate (PbWO$_{\mathrm{4}})$ crystals have been extensively studied and used in high energy physics calorimetry including the Forward Tagger Calorimeter in Hall B at Jefferson Lab. This detector consists of a matrix of 1.5x1.5x20 cm$^{\mathrm{3}}$ crystals arranged around the beamline to detect electrons and photons scattered at small angles. Due to the proximity to the beamline, the calorimeter is exposed to high radiation dose from electromagnetic background during data taking and can suffer from progressive degradation of the crystal light transmission. This can be monitored using the LED system that is part of the calorimeter equipment and is designed to inject a known amount of light in each crystal. The effects of radiation damage as a function of the crystal distance from the beamline have been studied analyzing the response to LEDs and cosmic rays, confirming the expected behavior as well as the spontaneous recovery due to thermal annealing when exposure to radiation is suspended. [Preview Abstract] |
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HA.00124: Proton Simulation Studies of Neutron Lifetime Measurement at NIST Jose Negron Precise knowledge of the neutron lifetime is crucial to understanding one of the four fundamental forces in the universe, the weak force, and understanding the ratio of hydrogen to helium formed in the early universe. Several major projects have been conducted in order to find the neutron lifetime using two different methods: The Bottle and The Beam methods. ~The neutron beam experiment underway at NIST shoots a beam of neutrons through an electrostatic trap where protons that decay from the free neutrons are trapped and then directed by a magnetic field to a proton detector and counted.~ Through Geant4 simulations, the neutron beam apparatus is reproduced, and proton interactions within the apparatus are simulated. ~Recent focus has been directed at studying proton arrival time at the detector, the effect of different electrostatic fields in the trap, and the proton count rate as a function of trap length. ~The end goal is to understand the size of systematic errors to ensure they contribute less than 2 seconds to the uncertainty in the neutron lifetime.~ [Preview Abstract] |
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HA.00125: Update of Neutron Spin-Transport Simulations for NSR Collaboration Zhaozhi Ye The Neutron Spin Rotation (NSR) collaboration has developed an apparatus to analyze the rotation of the plane of polarization of a polarized slow neutron beam passing through matter. The apparatus has been used to study the parity-odd weak interaction with unpolarized targets and a sensitivity capable of detecting a rotary power in the 10E-7rad/m range. Previous results support the prediction by the standard model. This poster summarizes updates done to nSpinSim, a fortran program that simulates the neutron polarimeter apparatus to be implemented in NIST in the updated version of the experiment. nSpinSim is a Monte-Carlo transport code aiming to help researchers understand the resolution in the high-precision measurements by studying systematic errors. Modifications include incorporation of realistic magnetic field maps, updating beam line components, and changing the implementation of how the code chooses neutron parameters from phase-space distributions. [Preview Abstract] |
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HA.00126: 3-Dimensional Hadronic Structure from Transverse-Spin Observables in High-Energy Collisions Joshua Miller, Justin Cammarota, Leonard Gamberg, Zhongbo Kang, Daniel Pitonyak, Alexei Prokudin, Nobuo Sato Quarks and gluons interacting inside of a hadron remains a complex system that needs to be analyzed. To probe inside of hadrons, they have to be collided at high energies, and to access their 3-dimensional (3D) structure, a particle with its spin transverse to its momentum must be involved. Such collisions can occur in semi-inclusive deep inelastic scattering (SIDIS), semi-inclusive e$^{\mathrm{+}}$e$^{\mathrm{-}}$ annihilation (SIA) and proton-proton collisions. Since the same fragmentation functions (FFs) and parton distribution functions (PDFs) enter these reactions, a global analysis can be performed that fits these functions. In this poster, I will present results from such a fit, where a replica/Monte Carlo method was used, give some computational details, and discuss the insight we can gain about quark-gluon correlations in hadrons and their 3D structure. [Preview Abstract] |
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HA.00127: Direct and Elliptical Flow Comparison at $\sqrt[]{s_{NN}} = 27$ GeV. Manuel Rosales Understanding the appearance and flow development of Quark Gluon Plasma (QGP) is crucial in improving our comprehension of the nearly perfect liquid that permeated the early universe. QGP created in heavy-ion collisions at the Relativistic Heavy Ion Collider (RHIC) has enabled researchers to comprehend the QGP through theoretical models. We present the analysis of anisotropic flow of the quark gluon plasma produced by Gold-Gold ion collisions at $\sqrt{s_{NN}}= 27$ GeV. In particular direct and elliptical flow comparisons of kaons determined by the Time Projection Chamber (TPC) and the Even Plane Detector (EPD) found at the Solenoid Tracker at RHIC (STAR). [Preview Abstract] |
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HA.00128: Z boson Measurements in pp Collisions at RHIC Thomas Limoges At the Relativistic Heavy Ion Collider (RHIC), pp collisions at center of mass energy 500 GeV often produce Z bosons. We will show results of the momentum balance between the Z boson and the away side jet (X$_{\mathrm{Zjet}})$ using PYTHIA 8 simulations. Using experimental data, muon and electron decay channels are used by STAR to find the Z boson and jet momenta ratio as well as the Z boson production cross section. We will show the feasibility of measuring this observable at STAR. The analysis may be used to further constrain parton distribution functions or to find insights into the matter produced in pp collisions. [Preview Abstract] |
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HA.00129: Constraining theoretical initial conditions models of heavy-ion collisions with Au$+$Au collision data at $\surd $s$_{\mathrm{NN}}=$27 GeV from the STAR detector at RHIC Skandaprasad Rao Jet suppression in heavy-ion collisions provided evidence in the 2000s of the formation of a quark-gluon plasma, which evolves as a strongly coupled liquid. The flow harmonics produced after the QGP freeze-out are known to exhibit a nonlinear hydrodynamic response to the initial geometry, characterized by eccentricity cumulants. Previous work has identified that the relationship can be well described with a linear$+$cubic estimator, leading to an exceptional prediction of the elliptic flow fluctuations using the initial ellipticity and estimator coefficients corresponding to the beam energy. By determining these coefficients for different energies, we can check many initial conditions models against data without computationally expensive hydro calculations. We present a full analysis of the flow harmonics $v_{\mathrm{1}}$,$_{\thinspace }v_{\mathrm{2}}$, and $v_{\mathrm{3}}$ from pions produced in 27 GeV Au$+$Au collisions using data from the Beam Energy Scan II at the STAR experiment at BNL's Relativistic Heavy Ion Collider. We also apply hydro code to simulated collisions to find the estimator coefficients best approximating the hydrodynamic response. We use the estimators to test several initial conditions models against the STAR results at this new energy. [Preview Abstract] |
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