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 SE: Undergraduate Research II |
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Chair: Sherry Yennello, Texas A&M University Room: Salon 5 |
Thursday, October 17, 2019 10:30AM - 10:42AM |
SE.00001: The STAR Forward Upgrade and Proton Spin Andrew Edwards One of the goals of the STAR (Solenoidal Tracker at RHIC) detector, located at Brookhaven National Laboratory, is to analyze polarized proton-proton collisions in order to constrain the polarized gluon contribution and its contribution to the spin of the proton. This is one of the motivations for an upgrade to the STAR detector, consisting of a Forward Tracking System (FTS) and Forward Calorimeter System (FCS). These components will be located in the forward rapidities 2.8 < η < 4.2. This upgrade will provide more complete information than previously available at STAR in this region. The FCS will include not only an electromagnetic calorimeter (ECal), but also STAR’s first hadronic calorimeter (HCal). We will describe the design of these two calorimeters and the different steps in their assembly procedure, e.g., the installation of the light guides on the ECal and the construction of the scintillator plates for the HCal. [Preview Abstract] |
Thursday, October 17, 2019 10:42AM - 10:54AM |
SE.00002: A Magnetic Field Mapper for the Test Apparatus of the nEDM experiment at Los Alamos National Laboratory Vuk Miodrag The LANL neutron Electric Dipole Moment (nEDM) experiment is an effort to set a sensitivity limit of a few \texttimes 10$^{\mathrm{-27}}$ $e$\textbullet cm on the electric dipole moment of the neutron, an order of magnitude smaller than the current limit. This measurement makes use of Ramsey's method of separated oscillatory magnetic fields. In a prototype test apparatus based on a small magnetically shielded room (MSR), ultra-cold neutrons precess in a magnetic field produced by solenoid. The magnetic field must be spatially uniform enough for a neutron dephasing time longer than the neutron storage time, such that the Ramsey fringes are well-resolved by the test apparatus. In order to measure the magnetic field precisely, a magnetic field mapper was designed within the MSR. The mapper itself is a carriage-mounted fluxgate controlled by multiple programs and a microcontroller, thus allowing the fluxgate to map desired areas within the MSR. Results of magnetic field measurements inside the apparatus, before and after degaussing the MSR and with and without the solenoid, as well as the design of the mapper will be presented. [Preview Abstract] |
Thursday, October 17, 2019 10:54AM - 11:06AM |
SE.00003: Characterization of Rn-220 as a Calibration Source in EXO-200 Nicole Khusid The overarching goal of EXO-200 is to observe a phenomenon known as neutrinoless double-beta decay of the $^{\mathrm{136}}$Xe isotope, in which a nucleus ejects two electrons with zero neutrino emissions, violating lepton number conservation. A successful detection of such an event would change our understanding of the Standard Model, identifying neutrinos as Majorana particles. The time projection chamber (TPC) uses liquid xenon, enriched in $^{\mathrm{136}}$Xe, as a decay source and detection medium. Its architecture allows for the reconstruction of decay events based on their position and energy from light and charge depositions. Decays throughout the $^{\mathrm{220}}$Rn decay chain may be used for calibration purposes, such as creating a more accurate position-dependent light response map using high-energy alpha decays, measuring fluid velocities, and using pulse coincidences within the chain to investigate detector response to small charge depositions. I present work toward characterizing $^{\mathrm{220}}$Rn as a calibration source for the EXO-200 detector, providing insight into the design of calibration sources for future large, low-background detectors like nEXO. [Preview Abstract] |
Thursday, October 17, 2019 11:06AM - 11:18AM |
SE.00004: Using Machine Learning to Extract Properties of Systems of Particles Ellen Gulian, Michael Kordell II, Rainer Fries In nuclear and particle physics, one is often presented with large systems of particles in the final state that emerge from complex dynamical processes. Identifying all of these processes is challenging with traditional analytical methods. In our work, we explore the possibility of extracting information from systems of particles using machine learning algorithms trained with pseudodata from simulations. We have written Python code to create systems of particles with features such as thermal motion of particles (of a given temperature), collective motion of particles (parameterized by a flow field), and decays of particles (from unstable heavier particles of given mass). These systems resemble those seen in experimental data as a result of high energy collisions of nuclei. We apply ensemble and neural network machine learning methods to pseudodata from our simulation code in order to analyze properties like temperatures and masses of the unstable mother particles. We study the performance of various algorithms in determining these underlying parameters. If proven feasible, applications include increasing our understanding of the hadronization process and the phenomenon of confinement by analyzing experimental data with machine learning. [Preview Abstract] |
Thursday, October 17, 2019 11:18AM - 11:30AM |
SE.00005: Feature Engineering for Small Angle Scattering ML/AI Yuke Wang, Tyler Martin Small-angle neutron scattering (SANS) is used to measure the thermodynamic and structural properties of materials. In SANS, a neutron beam interacts with a material and produces a scattering pattern depending on the nanostructure of the material. However, finding correlations between scattering patterns and material properties is difficult as the patterns produced are often similar and obfuscated by noise. Machine learning offer the promise of revolutionizing scientific data tasks, including analysis of scattering data. Unfortunately, due to the cost and slow acquisition time from SANS measurements limited data was available. Therefore, some of the most powerful ML techniques (deep learning) was not feasible and training traditional classifiers on the raw data resulted in low accuracy. The goal of this project was to engineer feature inputs for ML algorithms to extract information from small SANS datasets. The feature creation methods considered were manual feature engineering, and transfer learning. By comparing and combining physics based engineered features and learned features from simulations, a protocol was developed for building robust scattering classifiers and regressors. This project was contributing to a larger effort by NIST to develop a ML toolset to partially automate the process of analyzing/interpreting SANS data. [Preview Abstract] |
Thursday, October 17, 2019 11:30AM - 11:42AM |
SE.00006: ISLA Spectrometer Beam Focus and Mass Resolving Power Higher Order Optimization~ Yuyi Wan Nuclear physics plays a significant role in our modern life such as cancer treatment and national security. The product beams produced by certain nuclear reactions still remain unknown. Therefore, it is necessary for us to build a spectrometer that can separate the product beams in order to conduct further scientific research. ISLA (Isochronous Spectrometer of Large Acceptance) will allow experimental studies of reactions from re-accelerated rare isotope beams at the Facility for Rare Isotope Beams (FRIB), and enables us to distinguish different product beams (separating by mass-to-charge ratio) by looking at distributions of particles' time of flight through ISLA, instead of more commonly used physical separation. ISLA initial design consists of four magnetic dipoles and four magnetic quadrupoles, but as to how to achieve a high mass resolving power (the ability of the machine to identify nuclei by time-of-flight difference) in ISLA and how to produce a better focus at the end of ISLA still remained questioned. Recent progress has shown that the proposed solutions of adding multipoles or changing dipole quality do not contribute significantly to improving the resolving power but changing the dipole fringe field shape achieves our goals. [Preview Abstract] |
Thursday, October 17, 2019 11:42AM - 11:54AM |
SE.00007: Urca Nuclide Production in Type-I X-ray Bursts and Implications for Nuclear Physics Studies Grant Merz, Zach Meisel The thermal structure of accreting neutron stars is affected by the presence of urca nuclei in the neutron star crust. Nuclear isobars harboring urca nuclides can be produced in the ashes of Type I X-ray bursts, but the details of their production have not yet been explored. Using the code {\tt MESA}, we investigate urca nuclide production in a one-dimensional model of Type I X-ray bursts using astrophysical conditions thought to resemble the source GS 1826-24. We find that urca nuclei are generally produced late in the X-ray burst, during hydrogen-burning freeze-out that corresponds to the tail of the burst light curve. The relevant temperature for urca nucleosynthesis is therefore somewhat lower than the canonical conditions often assumed for nuclear physics experiments, altering the excitation energy range of interest in compound nuclei. [Preview Abstract] |
Thursday, October 17, 2019 11:54AM - 12:06PM |
SE.00008: Improving Measurements of Beam Dynamics for Fiber Harp System in Muon g-2 Experiment Dat Tran, Frederick Gray The Muon~$g$-2 experiment at Fermi National Accelerator Laboratory will improve the precision with which the muon's anomalous magnetic moment is known from 540 ppb to 140 ppb.~ ``Fiber harp'' beam monitoring devices provide a measurement of the time dependence of the muon beam's vertical and radial profiles by using scintillating fibers. The fiber harps measure the betatron tune (ratio of the betatron to cyclotron frequency) as a function of momentum. These measurements are crucial to understand the coherent betatron oscillation (CBO), which is a source of systematic error in the measurement of the muon spin precession. Furthermore, these measurements allow us to validate beam dynamics predictions from simulation models. Improvements in methods of extracting cyclotron and betatron frequencies as well as a better understanding of the uncertainties in extracting those frequencies will be presented. [Preview Abstract] |
Thursday, October 17, 2019 12:06PM - 12:18PM |
SE.00009: Prototype Readout System Software for The STAR Interlock Safety System at BNL Joseph D'Alesio RHIC, located at BNL, collides nuclei at relativistic speeds to artificially recreate the initial conditions of the universe. The STAR Collaboration studies these collisions using a detector, the \underline {S}olenoidal \underline {T}racker \underline {A}t \underline {R}HIC. The Interlock Safety System is responsible for monitoring and displaying parameters in the STAR control room. These parameters include the temperature and pressure of the TPC gas mixture, the Oxygen Deficiency Hazard status, the Uninterruptable Power Supply status and the water cooling system status. If these parameters fall outside an accepted range, alarms will sound to notify the control room. The readout system and software allow for the shift operator to adjust detector variables while the experiment is running and thus prevent circumstances in which fires and explosions are likely. This project focuses on upgrades to the Interlock monitoring system. The current Interlock Readout monitor uses a VME to communicate with various STAR systems while the upgraded monitor uses a \underline {P}rogrammable \underline {L}ogic \underline {C}ontroller interfaced to a PC. Device support for the upgraded monitor has been written and compiled using a prototype input/output controller program to communicate to the new readout PLC. Functionally, the existing and upgraded system will have the same capabilities. However, the new readout system will be easier to maintain and more easily updated to include, for example, additional safety signal outputs. In turn, this will result in a critical readout system prepared for future operations. [Preview Abstract] |
Thursday, October 17, 2019 12:18PM - 12:30PM |
SE.00010: E1039 Luminosity Monitor Testing and Installation Emily Branson E1039 will collide a 120 GeV unpolarized proton beam from Fermi National Accelerator Laboratory with hydrogen and deuterium targets polarized transversely to the beam. Then, asymmetries of dimuon pairs produced in the Drell-Yan process will be measured to find the Sivers Function, a transverse momentum dependent parton distribution function. A non-zero measurement of the Sivers Function implies orbital angular momentum of the quark sea. In measuring these asymmetries, variances in beam luminosity must be accounted for, as changes in the beam could skew our data. For this reason, E1039 is outfitted with a luminosity monitor for measuring beam intensity and accuracy. The monitor is composed of four hodoscopes on an aluminum rail and is installed in the target cave at 90 degrees relative to the beam line. The testing and installation of this beam will be presented. [Preview Abstract] |
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