Bulletin of the American Physical Society
2020 Fall Meeting of the APS Division of Nuclear Physics
Volume 65, Number 12
Thursday–Sunday, October 29–November 1 2020; Time Zone: Central Time, USA
Session NA: Conference Experience for Undergraduates Poster Session IV (4:00pm - 4:35pm) |
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NA.00001: Neutron dEtector with Xn Tracking (NEXT) Aaron Kindred, Mustafa Rajabali, Robert Grzywacz, Joe Heideman, Shree Neupane The neutron detector NEXT will allow higher accuracy studies for beta-delayed neutron emission, while maintaining neutron-gamma discrimination. NEXT utilizes thin, segmented, inorganic scintillators which are paired with photosensitive devices to increase detection efficiency for energy measurement and tracking capabilities. NEXT is currently in a prototype phase and is continuously being modeled with GEANT4 based simulation software, NEXTSim. Neutrons and gamma-rays with energies ranging from 100 keV to 10 MeV have been simulated and show consistent results in regards to scattering patterns and energy resolution within NEXT. Sample simulation outputs will be shown and described in this work. This work is funded by NSF grant NSF-1919735, sub-grant A20-0254-S001. [Preview Abstract] |
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NA.00002: Abstract Withdrawn
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NA.00003: G4Beamline simulation for the study of $^{\mathrm{13}}$Be isomers Yannick Gueye, Paul Gueye, Thomas Baumann The MoNA Collaboration will study neutron-unbound states of $^{\mathrm{13}}$Be in a dedicated experiment scheduled to run in September 2020 at the National Superconducting Cyclotron Laboratory. The experimental setup consists of a 76 MeV/u $^{\mathrm{14}}$Be incident beam that will imping on a beryllium target placed in front of a newly constructed telescope to identify the charged fragments produced during the reaction process. The telescope is composed of two tetra lateral position sensitive silicon detectors, five silicon PIN diode detectors, one calorimeter made of one cesium iodide crystal and a veto scintillator paddle. All the elements were coded into G4Beamline which is a Geant4 based simulation developed to model accelerator beamlines. The fragments exiting the telescope that deposited energy inside the veto detector were identified and studied using the ROOT analysis framework. We will present and discuss the results from this work. [Preview Abstract] |
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NA.00004: Studying neutron-unbound states produced from a Na-30 beam Grant Bock Invariant mass spectroscopy is a well-established technique used to recover information about neutron-unbound states that are not directly measurable, due to very short decay timescales on the order of 10$^{\mathrm{-21\thinspace }}$s. Measurements of these systems provide crucial benchmarks to help evaluate and improve theoretical models. In 2016, the MoNA Collaboration conducted a measurement of the O-26 half-life during which the Coupled Cyclotron Facility and the A1900 fragment separator at the NSCL supplied F-27, Ne-28, Ne-29, and Na-30 secondary beams produced via projectile fragmentation. These beams were subsequently directed onto a beryllium target. The main focus of the data set was given to the events in which one-proton knockout from F-27 populated neutron-unbound states in O-26. The goal of the current project is to extract the measured decay energy spectra for neutron-unbound states produced from the Na-30 beam and compare them to previous measurements while also searching for new unbound states with decay energies less than 3 MeV. [Preview Abstract] |
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NA.00005: Using Adversarial Networks to Generate Realistic Structure Function Surfaces Andrew Hoyle, Michelle Kuchera, Raghu Ramanujan, Nobuo Sato, Pawel Ambrozewicz, Wally Melnitchouk, Zach Nussbaum The purpose of this project was to develop a Generative Adversarial Network (GAN) architecture which would generate surfaces of nuclear structure functions as a function of Bjorken $x$ and $Q^2$. The architecture is based on a modified version of a Wasserstein GAN (wGAN) where the generator produces the structure function surfaces and the discriminator calculates a cross section surface from the structure function and evaluates its validity. Therefore, this model differs from a traditional wGAN in that it is semi-supervised, meaning we are not supervising on the quantity of interest. The model was trained on both theoretical and mock experimental data of both inclusive and semi-inclusive deep inelastic scattering events. The theoretical data were produced by a script which calculates the structure function and cross section values within a specified grid of kinematic variable values. The mock experimental data were generated by Pythia, but transformed into binned experimental-like data. Preliminary results indicate that GANs can be used to generate the structure functions. We explore the most effective architecture and tuning parameters to give the desired results. Results will be presented alongside metrics showing how accurate the generated surfaces are to their true values. [Preview Abstract] |
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NA.00006: Calculation of Neutrino Events in Binary Neutron Star Mergers. Loida Rosado Del Rio, Kate Scholberg Binary neutron star mergers produce thermal neutrinos that can be detected using detectors such as Super-Kamiokande and the DUNE far detector. Using a software called SNOwGLoBES we can simulate a neutrino flux from a merger at 10 kpc and calculate its interaction and event distribution rates. We found that for said merger 4,000 events in DUNE will be detected at 10 kpc, of which 3,500 will be electron neutrino on argon 40 interactions. We also saw that, comparing the flux for this merger and for a core-collapse supernova, while the event rates for both were similar, the neutrino flux for this merger was higher by one order of magnitude than the flux for the supernova. [Preview Abstract] |
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NA.00007: Abstract Withdrawn
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NA.00008: Collimator optimization for BL3: Next generation neutron beam lifetime experiment Paul Harmston The BL3 experiment intends to accurately measure the lifetime of the free neutron via the beam method. Previous beam experiments were limited by statistics. A primary goal of BL3 is to reduce statistical and systematic uncertainties to resolve the discrepancy between beam and bottle methods with greater confidence. To evolve our knowledge of systematic effects a solid understanding of the neutron beam spot size on the detector is needed to verify near complete detection. A series of simulations in the ray tracing software MCstas was performed to verify spot size and maximize both the neutron flux and count rate. [Preview Abstract] |
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NA.00009: An Investigation of Inclusive Differential Jet Shapes with Monte Carlo Simulations at RHIC Energies Apurva Narde Heavy-ion collisions allow us to investigate the nature of quark-gluon plasma (QGP) which was predominant in the initial moments of the early universe. In the aftermath of hard scattered partons, the collection of high transverse momentum particles consisting of quarks and gluons form the basis of a jet. Jets interact strongly with the QGP medium, also known as jet quenching, which changes the energy flow within a jet. Thus, differential jet shape observable serves as a natural choice of a probe to investigate the detailed properties of QGP. In this study, Monte Carlo simulations of proton+proton and Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV energies generated in Pythia and Angantyr event generators are used to examine the jet shapes. Jets are reconstructed using the anti-kT sequential recombination algorithm with R = 0.4. The jet shapes are measured for full jets and charged only jets to investigate the effect of the neutral content, kinematic selection, and background effects to further understand the selection biases. [Preview Abstract] |
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NA.00010: Neutron-Induced Reaction Cross-Section Measurements of Short-Lived Nuclei Olivia Dickinson, Fnu Krishichayan, Sean Finch, Calivn Howell, Werner Tornow Nuclear reaction cross-section data, such as (n,2n), (n,$\gamma )$ \begin{figure}[htbp] \centerline{\includegraphics[width=0.19in,height=0.19in]{310720201.eps}} \label{fig1} \end{figure} and ($\gamma $, \begin{figure}[htbp] \centerline{\includegraphics[width=0.13in,height=0.19in]{310720202.eps}} \label{fig2} \end{figure} n) producing short-lived isotopes (s $\le $ T$_{\mathrm{1/2\thinspace }}\le $ m) are critically important to a breadth of scientific fields including applications relevant to national security, medical isotopes, and fission and fusion reactor technology. However, not much experimental data is available due to various associated limitations including poor counting statistics. This limitation can be overcome by using the cyclic activation technique by way of a fast-irradiated sample transfer system. With the availability of the fast transfer system, RABITTS at TUNL, the cyclic activation technique can be used to study such reaction cross sections for nuclei having half-lives between seconds and minutes. The primary isotopes of interest are $^{\mathrm{73}}$Ge, $^{\mathrm{77}}$Ge, $^{\mathrm{91}}$Mo, $^{\mathrm{114}}$In,$^{\mathrm{116}}$In, and will be produced using quasi-monoenergetic neutron beams from the 10 MV Tandem laboratory at TUNL. An array of highly efficient and broad energy germanium detectors will be used for the gamma-ray counting. A detailed energy and efficiency calibration of the detector array along with the conceptual and computational work related to the project will be presented. [Preview Abstract] |
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NA.00011: Determining the total yield of alpha-capture reaction products from measurements in a limited sample of charge Elizabeth Alters, Jerry Hinnefield, Chris Seymour, Luis Morales, Manoel Couder The St. George recoil separator at the University of Notre Dame is devoted to studying alpha-capture reactions produced by a heavy beam using inverse kinematics. This method, as opposed to the standard light beam method, reverses the kinematics of the reaction by accelerating the heavy element while using the lighter Helium as the target. St. George transports the recoiling reaction products into the detection system, while simultaneously rejecting the beam particles that do not interact with the target. In order to determine the total reaction yield from the most abundant charge states, the charge state distribution of the reaction products emerging from the helium gas target must be ascertained. The program ETACHA has been used to calculate charge state distributions for 20Ne projectiles and 24Mg products passing through the helium gas target, and these calculations were combined to determine the expected distribution of charge states of detected 24Mg reaction products. [Preview Abstract] |
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NA.00012: Ab-Initio Calculations of Electric Dipole Moments in Light Nuclei Paul Froese, Petr Navrátil In any finite system, the presence of a non-zero permanent electric dipole moment (EDM) would require both parity (P) and time-reversal (T) violation. The standard model predicts a very small CP violation and consequently any observation of the EDM would imply physics beyond the standard model. Thus, EDMs have long been proposed as a way to test these fundamental symmetries. Experimental studies have placed upper bounds on neutron, nuclear and atomic EDMs, while theoretical studies have calculated their magnitudes using a variety of methods. In particular, it has been found that nuclear structure in certain nuclei can enhance the EDM. Here, we use an ab-initio no-core shell model (NCSM) framework to theoretically investigate the magnitude of the nuclear EDM. We calculate the EDMs of several light nuclei using chiral two- and three-body interactions and a PT-violating Hamiltonian based on a one-meson-exchange model. We will present a successful benchmark calculation for 3He, as well as results for more complex nuclei including 6Li, 7Li, 9Be, and 13C. These calculations will allow us to better understand which nuclei may have enhanced EDMs, and thus allow us to suggest which ones may be good candidates in the search for a measurable permanent dipole moment. [Preview Abstract] |
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NA.00013: Data Evaluation of $^{\mathrm{9}}$C Beshoi Grees TUNL is part of an international network of Nuclear Structure and Decay Data evaluators (NSDD) and the U.S. Nuclear Data Program (USNDP) that perform evaluations of published nuclear experimental articles for the Evaluated Nuclear Structure Data File (ENSDF). ENSDF is a complete evaluation of all experimental nuclear data on a particular nuclide and contains a dataset of recommended nuclear properties and parameters of that particular nuclide and thus this data is important for various nuclear applications including, but not limited to, planning and interpreting scientific experiments, nuclear medicine, reactor design and operation, and radiation safety. All published data on $^{\mathrm{9}}$C was reviewed and evaluated. The current $^{\mathrm{9}}$C ENSDF was updated and prepared to submit, and a new dataset of recommended properties, such as decay modes, level energies, and radiation properties was produced. [Preview Abstract] |
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NA.00014: Simulations of Proton in the BL3 Experiment Trang Bui For over 70 years, scientists have been performing measurements of the neutron lifetime, finding a world average of approximately 15 minutes. However, the beam method and the ultracold neutron storage method gave the average value that currently differs by 8.7 seconds (4 standard deviations). The BL3 experiment at the National Institute of Standards and Technology, USA, aims to improve the precision of one of the beam-type measurements in the hope of resolving this discrepancy. The present goal is to decrease uncertainty in the experiment to 3 seconds. In the experiment, a neutron beam passes through a quasi-Penning trap, and decay protons are trapped electrostatically between mirror electrodes at $+$800V, central trap electrodes at 0V, and door electrodes at $+$800V, and magnetically by an axial magnetic field that does not vary by more than 0.2{\%} of its average. When enough decay protons have accumulated, the trap will open and decay protons in the trap follow a bend in the magnetic field to a silicon detector, where they are counted. In this project, we studied the motion of protons moving around in the BL3 proton trap by running simulations in a program called 'Kassiopeia' developed for the KATRIN experiment in Karlsruhe, Germany. We used the program SRIM (Stopping and Range of Ions in Matter) to simulate backscattered protons.~ [Preview Abstract] |
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NA.00015: An investigation of the $\overline{u}$ - $\overline{d}$ asymmetry in the proton sea through a combined Statistical and Meson Cloud Model Lucas Ehinger, Mary Alberg Recent experimental investigations have found an asymmetry in the distributions of $\overline{u}$ and $\overline{d}$ within the proton; a result which cannot be well explained through simple perturbative gluon splitting. Instead, this result is better explained by fluctuation of the proton into meson-baryon pairs. We use the Light Front formulation of the Meson Cloud Model (MCM) to describe this proton-pion cloud system as an expansion of the proton with meson-baryon pairs. Using the principle of detailed balance, we develop statistical models for the proton and the meson and baryon parton distributions. To avoid double counting of expanded states within our MCM, we determine a “bare proton” distribution by subtracting these expanded meson-baryon states from our proton statistical model. We then use Monte Carlo analysis to determine the momentum-dependence of our $\overline{u}$-$\overline{d}$ asymmetry, after which we evolve our results to higher $Q^2$ to allow for comparison with experimental data. [Preview Abstract] |
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NA.00016: Fast Neutron Activation of Ubiquitous Materials Michelle Lee, Oluwatomi Akindele, Keenan Thomas, Pedro Guillamon, Jordan Sabella, Ross Meyer, Howard Shugart, Eric Norman Nuclear explosions can expose ubiquitous materials to large numbers of neutrons producing a variety of radioactive isotopes. In an attempt to simulate such phenomena from both fission and thermonuclear explosions, irradiations with \textasciitilde 3 and \textasciitilde 14 MeV neutrons were performed on 25 different materials using LBNL's 88 Inch Cyclotron. For each neutron energy, the expected radioisotopes, half-lives, and gamma- ray energies were deduced using existing data from the National Nuclear Data Center and the Table of Radioactive Isotopes. The beta-delayed gamma rays emitted from the activated targets were measured with three different high-purity germanium detectors at varying times following irradiation. Using this data, we were able to calculate the initial activities of one or more radioisotopes from each activated target. By examining the ratios of activities of different isotopes from the 3 and 14 MeV data, we have been able to identify several materials that are particularly sensitive to the neutron energy spectra. Preliminary results from this work will be presented. [Preview Abstract] |
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