Session DB01: Undergraduate Research I

Limiting Radioactivity to Facilitate Next-Generation Rare Event Detection

In the search for rare events, a constant problem with precise measuring devices is the radioactivity of the materials used to construct the detector. Most metals and minerals contain Uranium-238, which leads to a long decay chain of various heavy elements that contribute noise. Even in trace amounts, this background becomes a limiting factor for signal detection. This project aims to configure a Germanium-IV detector to investigate potential candidates for next-generation detector design. Initial stages of setup and data collection indicate that a physical malfunction exists preventing the desired investigations. As a precursor, data was accumulated for analysis to bear insight into the nature of the malady. After ten weeks of gathering and parsing through the data obtained, a technique was devised that allows for an accurate extraction of the upper limit of sample radioactivity using the detector in its current state.   

Improving the Design of an Alpha Particle Detector Collimator

The BL3 experiment will be performed to investigate a 4.3 σ discrepancy between measurements of the neutron lifetime using a cold neutron beam versus trapped ultracold neutrons. An important aspect of BL3 is measurement of the neutron capture flux by detecting the alpha and triton particles from reaction with a thin Li-6 foil in the neutron beam. Thus, the precise positioning of alpha detectors and apertures is required for detection efficiency and uniformity. A detector support has been redesigned for the BL3 apparatus which rigidly mounts to the vacuum chamber and allows PIPS detector to be swapped out without accessing the apertures. This design uses kinematic couplings to make fine adjustments to the aperture orientation, and allows for precision mounting of caustic apertures, which allow for enhanced detection uniformity.   

Data Analysis for the XEM2 Experiment to study High-Momentum Nucleons and Quarks

Experiments conducted using the Continuous Electron Beam Facility (CEBAF) at Jefferson Lab help us access different distance scales, and probe quarks, nucleons as well as nuclei by varying the wavelength of the virtual photon. The XEM2 experiments made concurrent measurements using two high momentum spectrometers (HMS and SHMS) in experimental Hall C of Jefferson Lab. Each spectrometer contains several particle detectors, to examine short-range correlations at high momenta, the European Muon Collaboration (EMC) effect and super-fast quark distributions. I will be presenting data quality checks performed for the particle detectors and preliminary normalized yields used to obtain nuclear cross sections.   

Developing an Outgassing Model for Candidate Detector Materials in nEXO

Neutrinoless double beta decay is a hypothesized nuclear process that would confirm the Majorana nature of neutrinos. nEXO is an upcoming search for this decay in Xenon-136 using a high voltage time projection chamber (TPC) filled with 5 tonnes of isotopically enriched liquid xenon (LXe). nEXO reconstructs energy deposits through measurements of ionization electrons and scintillation photons produced by such decays within the TPC. However, the outgassing of electronegative impurities via diffusion from detector materials into the LXe bulk compromises the measurement of ionization electrons. In our study, we develop an outgassing model that quantifies this diffusion of impurities from candidate materials to qualify materials for use in the upcoming nEXO experiment.   

Numerical Study of Metastable Spherical Gluon Plasma Balls in Large-N Gauge Theories via AdS/CFT

In this study, we investigate gluon plasma balls in large-N confining gauge theories, through the lens of their gravity dual in the AdS/CFT correspondence. The unconfined gluon plasma can be represented as an AdS black hole, whereas the confining vacuum corresponds to the AdS soliton. In prior work, Aharony et al. proposed the existence of metastable plasma balls by numerically constructing a planar domain wall solution that interpolates between the plasma phase and the confining phase. Our research extends this work by using the ADM formalism of general relativity to numerically compute an interpolating solution which represents a spherical plasma ball surrounded by a confining vacuum at the deconfinement temperature, where it undergoes a first-order phase transition. Looking forward, we intend to study the thermodynamic properties of the plasma ball, including its energy density, pressure distribution, surface tension, and heat expansion by analyzing the gravitational field data from a dual perspective.   

Monte Carlo Simulation of the NSR Collaboration apparatus at NIST

The NSR collaboration has designed a neutron spin polarimeter to measure deviations in the average spin rotation of a beam of neutrons in the range of 1E-7 rad/m. The collaboration is considering using this polarimeter at the NGC arm of the NIST reactor to carry out experiments to test a predicted class of short-range spin dependent forces that affect neutron polarization as they pass close to other dense masses of baryons. If these forces are demonstrated to exist, this would extend the standard model of particle physics. Over the summer we adapted a Monte Carlo simulation of the instrument in MCSTAS to use the NGC neutron phase space and gauge the ability of the MCSTAS instrument to accurately measure pre-determined tilts we put in the neutron beam. We also investigated possible systematic errors due to spin rotations from magnetic fields by looking at changes in the neutron beam's angular and wavelength distributions downstream from the target as a function of target configuration.   

Developing and Testing the Helium-3 Polarization System and SQUID Magnetometers for nEDM@SNS SOS Apparatus

The neutron electric dipole moment (nEDM) is a parameter that can probe the charge-parity and time-reversal symmetries of nature and could have profound implications for the origin of the baryon asymmetry in the Universe. The current best measured limit of the nEDM has a precision of 1.1 x 10^-26 e cm, and the goal of the nEDM@SNS collaboration is to improve this sensitivity by two orders of magnitude at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory. The experiment will use polarized Helium-3 and ultra-cold neutrons for the spin-dependent neutron capture reaction in uniform magnetic and strong electric fields. In this project, we aim to develop and test a Metastability Exchange Optical Pumping (MEOP) Helium-3 polarization apparatus and the Superconducting Quantum Interference Device (SQUID) magnetometers for the Systematic Operations Studies (SOS) at the NC State PULSTAR, which will serve as a test run to the larger scale experiment at Oak Ridge. In this talk, we report our progress and challenges in constructing the MEOP gas handling system and testing a SQUID magnetometer. We also outline our future plans for improving the performance of these devices.