Author ORCID Identifier
Document Type
Dissertation
Date of Award
2024
Degree Name
Doctor of Philosophy (PhD)
Department
Physics
First Advisor
Jing JL Liu
Abstract
Coherent elastic neutrino-nucleus scattering (CEvNS) was first proposed in 1974. Despite having the largest cross-section among all low-energy neutrino couplings predicted in the Standard Model (SM), CEvNS detection remains challenging due to its only experimental signature being a low-energy nuclear recoil. In 2017, the COHERENT collaboration successfully observed CEvNS for the first time. A 14.6 kg low-background doped CsI at room temperature was placed 20 meters away from the 1.4 MW Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory (ORNL). The SNS's pulsed proton beam provides exceptional background rejection and high-intensity neutrinos, making it ideal for CEvNS detections. CryoCsI, the proposed prototype, is a cryogenic undoped CsI scintillating detector, which has a much lower energy threshold potentially down to 0.5 keV$_{nr}$ compared to the doped CsI. This enhanced sensitivity of CryoCsI allows for the observation of more CEvNS events. Precise measurements of CEvNS can not only validate the predictions of the SM but also explore new physics. In conjunction with other COHERENT detectors, CryoCsI has the potential to achieve world-leading sensitivities in a broad range of physics topics within and beyond the SM. The sensitivities of CryoCsI to hidden-sector dark matter, non-standard neutrino interactions, and neutron radius are explored. This thesis delves into the construction of CryoCsI and efforts to enhance its light yield from 20 to $50 \pm 2$ photoelectrons (PE) per keV electron-equivalent (keV$_{ee}$). It will address challenges with cryogenic SiPMs, including inferior energy resolution, optical cross-talk, and potential limitations on detecting rare events. Understanding the light yield of scintillating detectors for nuclear recoils is crucial, as explored through alpha-particle and neutron quenching factor (QF) measurements. A QF of approximately 15\% was measured using a neutron beam at the Triangle Universities Nuclear Lab (TUNL). Proposed solutions to challenges like the overshoot effect observed in PMTs will be discussed. Additionally, the thesis will explore design considerations for minimizing background noise and optimizing the CsI crystal's shape through optical simulations.
Subject Categories
Physics
Keywords
Coherent elastic neutrino-nucleus scattering, cryogenic scintillator, dark matter, neutrino
Number of Pages
133
Publisher
University of South Dakota
Recommended Citation
Ding, Keyu, "Development Of Cryogenic Scintillation Detectors For The Search Of New Physics" (2024). Dissertations and Theses. 295.
https://red.library.usd.edu/diss-thesis/295