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 SB: Instrumentation I |
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Chair: Maxim Mai, GWU Room: Salon 2 |
Thursday, October 17, 2019 10:30AM - 10:42AM |
SB.00001: High Luminosity Spin-Polarized Target for the SpinQuest Experiment Joshua Hoskins The SpinQuest collaboration will measure the sea quark Sivers asymmetry using Drell-Yan production from the 120 GeV proton beam of the Fermilab Main Injector incident on transversely polarized proton and deuteron targets. Measuring a nonzero Sivers asymmetry would provide strong evidence for nonzero orbital angular momentum of sea quarks. The use of both polarized hydrogen and deuterium targets will provide an independent extraction of the u\textunderscore bar and d\textunderscore bar contributions in the range of 0.1 \textless x \textless 0.5. In order to provide high figure-of-merit measurements of the sea quark Sivers functions, high luminosity, transversely polarized targets are required. The polarized target system constructed by UVA-LANL consists of a 5T, split-coil, superconducting magnet and uses a 140 GHz microwave source to provide highly polarized protons and deuterons via dynamic nuclear polarization (DNP). The expected average target polarization for SpinQuest is 80{\%} and 32{\%} for the hydrogen and deuterium targets, respectively. A brief overview of the SpinQuest experiment and a survey of the high luminosity polarized target will be presented. [Preview Abstract] |
Thursday, October 17, 2019 10:42AM - 10:54AM |
SB.00002: Thermal Analysis and Simulation of the Superconducting Magnet in the SpinQuest Experiment at Fermilab Zulkaida Akbar The SpinQuest experiment at Fermilab aims to measure the Sivers asymmetry for the $\bar{u}$ and $\bar{d}$ sea quarks in the nucleon using the Drell-Yan process. The experiment will utilize a target system consisting of a 5T superconducting magnet, transversely polarized NH$_3$ and ND$_3$ targets, a $^4$He evaporation refrigerator, a 140 GHz microwave source and a large pumping system. The proposed beam intensity is 1.5$\times$10$^{12}$ of 120 GeV proton/sec. A quench simulation in the superconducting magnet is performed to determine the maximum intensity of the proton beam before the magnet transition to the resistive state. A GEANT based simulation is used to calculate the heat deposited in the magnet and the subsequent cooling processes are modeled using the COMSOL Multiphysics. [Preview Abstract] |
Thursday, October 17, 2019 10:54AM - 11:06AM |
SB.00003: E-1039 FPGA Trigger Noah Wuerfel The SpinQuest (Fermilab E-1039) experiment will measure an azimuthal asymmetry in the Drell-Yan production of $\mu^+$ $\mu^-$ pairs from 120 GeV/c proton interactions with polarized nucleons to extract the Sivers function for $\bar{u}$ and $\bar{d}$. A large combinatorial background from muons produced in the beam dump requires a trigger which is capable of identifying dimuon pairs originating from the target in a high rate environment. The trigger system consists of four stations of scintillator hodoscopes whose 96 channels are digitized and processed by field-programmable gate array (FPGA) based VMEbus modules. TDC outputs can be adjusted channel-by-channel in 1-ns steps for realignment with the beam RF clock. Hodoscope hit patterns are compared to predetermined sets, chosen from Monte Carlo simulations, in a tiered lookup table to generate trigger decisions. The design and current status of the FPGA trigger are presented and planned upgrades to the trigger logic discussed. [Preview Abstract] |
Thursday, October 17, 2019 11:06AM - 11:18AM |
SB.00004: Tracking Low-Momentum Protons in a Radial Time Projection Chamber David Payette A Radial Time Projection Chamber (RTPC) has been designed and built for installation in Jefferson Lab’s Hall B as part of the BONuS12 (Barely Off-shell Nucleon Structure) experiment. The goal of BONuS12 is to accurately measure the structure function of the neutron by scattering the 11 GeV electrons from the upgraded CEBAF and detecting them with the CLAS12 spectrometer. Deuterium gas is used as an effective neutron target, and the new RTPC is used to detect low-momentum spectator protons. Protons follow a curved path in the 5 Tesla solenoid that is part of CLAS12, ionizing the He-CO2 gas in an annular drift region surrounding the target. These ionization electrons are radially drifted outwards, amplified using cylindrical GEM (Gaseous Electron Multiplication) foils and recorded using readout pads located along the entire outer face of the cylindrical detector. Tracking software uses the signals from these pads to build tracks, which are reconstructed into the drift region using the arrival times of the signals and the positions of the pads. The proton momentum is measured from the track’s curvature and thus used to extract information about the struck neutron. We will present the status and performance of the tracking hardware and software. [Preview Abstract] |
Thursday, October 17, 2019 11:18AM - 11:30AM |
SB.00005: ABSTRACT WITHDRAWN |
Thursday, October 17, 2019 11:30AM - 11:42AM |
SB.00006: Status of the JLab Eta Factory (JEF) experiment Simon Taylor The JLab Eta Factory (JEF) experiment is designed to study various decays of the $\eta$ meson using the GlueX detector in Hall D at Jefferson Lab. The experimental program includes measuring the Dalitz distribution from $\eta\to\pi^+\pi^-\pi^0$ to determine the up/down quark mass difference, looking for evidence for new C-violating/P-conserving physics, providing input to higher-order chiral perturbation theory calculations, and searching for evidence of dark matter. The latter two items rely on measuring the rare $\eta \to \pi^0\gamma \gamma$ decay mode that will require an upgrade to the existing GlueX equipment, which is a fixed target apparatus based on a 2-Tesla solenoid magnet. Charged tracks are reconstructed using drift chambers within the magnet and neutral particles are detected in the forward direction in the Forward Calorimeter (FCAL), an array of lead glass blocks. The JEF program calls for replacing the $\sim$80$\times$80 cm$^2$ region of the FCAL around the beam line with an array of 2$\times$2$\times$20 cm$^3$ lead tungstate crystals. The status of this upgrade will be presented. [Preview Abstract] |
Thursday, October 17, 2019 11:42AM - 11:54AM |
SB.00007: Gamma-Calibration of the Scattered-Particle Scintillators for MUSE Anne Flannery The MUon Proton Scattering Experiment (MUSE) at the Paul Scherrer Institute seeks to address the proton radius puzzle through measuring the muon-proton and electron-proton elastic cross sections in the same experiment. The MUSE setup includes scattered-particle scintillators (SPS) which are part of the event trigger and help with particle separation and reaction identification via time-of-flight measurements. The SPS system consists of two front walls with eighteen 120-cm long EJ-204 scintillation bars and two rear walls with twenty-eight 220-cm long bars. The wall pairs are placed symmetrically about the beam line. The vertical scintillators are read out at their long ends with Hamamatsu R13435 photomultiplier tubes. The precise knowledge of the detection threshold and efficiencies, as well as quantitative comparisons with Monte Carlo simulations, require an absolute energy calibration of the scintillators. In this presentation, we will discuss the gamma-calibration methods for the SPS detectors. [Preview Abstract] |
Thursday, October 17, 2019 11:54AM - 12:06PM |
SB.00008: Construction of a Set of Gas Electron Multiplier Detectors with Novel Design Jesmin Nazeer, Ishara Fernando, Tanvi Patel, Michael Kohl A set of Gas Electron Multiplier (GEM) detectors opimized for low material budget has been constructed for use in low-energy tracking applications. A novel GEM construction technique is used where all layers are stretched and assembled mechanically within a double frame. The readout is based on Analog Pipeline Voltage (APV) frontend cards and Multi-Purpose Digitizers (MPD). The key features of these detectors allow them to be used very flexibly in high-rate environments for high-resolution charged particle tracking. The present status of the construction and performance of the GEM detectors will be discussed. [Preview Abstract] |
Thursday, October 17, 2019 12:06PM - 12:18PM |
SB.00009: Progress toward a measurement of the shape of the $^{14}$C $\beta$ spectrum Elizabeth A. George, Paul A. Voytas, L.D. Knutson Precision beta-decay experiments can constrain possible extensions to the Standard Model of the weak interaction. We report on progress toward a new measurement of the $^{14}$C beta spectrum shape as a test of the strong form of the Conserved Vector Current hypothesis. This measurement will complement a previous measurement of the shape factor in the $^{14}$O analog transition, which was carried out with a superconducting beta spectrometer\footnote{L.D. Knutson \textit{et al.}, Rev. Sci. Instrum. \textbf{82}, 073302 (2011).} and achieved a relative precision of 3\% on the linear term of the shape factor\footnote{E.A. George \textit{et al.}, Phys. Rev. C \textbf{90}, 065501 (2014).}. A comparable precision is the goal of the $^{14}$C shape measurement. For this measurement we have constructed a new iron-free magnetic beta spectrometer with the same geometry as the $^{14}$O spectrometer but with conventional field coils. Because of the low $^{14}$C endpoint energy (156 keV), scattering within the spectrometer may cause energy-dependent distortions at the target precision. We report on the design of the spectrometer, Monte Carlo simulations aimed at addressing scattering issues, and results from initial test runs. [Preview Abstract] |
Thursday, October 17, 2019 12:18PM - 12:30PM |
SB.00010: Radioactive Source Insertion System for the Nab Experiment Christopher Hayes The Nab experiment at the Spallation Neutron Source is designed to provide high statistics measurements of the electron-neutrino correlation coefficient and the Fierz interference term in free neutron beta-decay. Of critical importance to the success of Nab is the use of a Radioactive Source Insertion System (RSIS) designed to insert weak conversion-electron sources of known energy into the 70K Ultra High Vacuum (UHV) bore of the Nab magnet--spectrometer. The RSIS incorporates precise positioning of the sources throughout the neutron decay volume to scan individual pixels of two segmented Silicon detecters placed at 5 m and 1.5 m from the source. Beta response functions from individual pixels can then be evaluated for energy loss and calibration of detectors. I will discuss detailed aspects of the RSIS design features including the UHV system outside the magnet, the electro-mechanical system, and requirements for precise motion of the sources. [Preview Abstract] |
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