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MITIGATION of BACKGROUNDS for the LARGE UNDERGROUND XENON DARK MATTER EXPERIMENT

Lee, Chang
http://rave.ohiolink.edu/etdc/view?acc_num=case1427482791

Abstract Details

2015, Doctor of Philosophy, Case Western Reserve University, Physics.
While the existence of particle dark matter is widely accepted through multitude of astrophysics evidence, its exact nature remains mysterious. It is expected to comprise the local galactic halo, and one of the most favored candidates, weakly interacting massive particle (WIMP), is hypothesized to interact with baryonic matter. Such an interaction can be detected in a radio-quiet low-threshold detector such as the large underground xenon (LUX) detector. The LUX is a dual-phase xenon time projection chamber (TPC), and it operates at Sanford Underground Research Facility in Lead, SD. Analysis of the first science data with a 86.3 days live-time from LUX yielded the best spin-independent WIMP-nucleon cross-section exclusion limit to date, with the lower limit of $7.6\times10^{-46}$~cm$^2$ at 33~GeV/c$^2$ with a 90\% confidence level. This thesis consists the following chapters. The case for cold dark matter from the current cosmological observations is reviewed. The natures of the expected WIMP-nucleon scattering signal and the techniques to discriminate the background events are discussed. Principles of the dual-phase TPC are explained, with details of the LUX hardware. The original works for this thesis follows. A campaign to remove radioactive noble impurities from the target xenon is described in depth. A position reconstruction algorithm based on comparison of observed data to simulation is developed. Background events from the detector's internal walls are studied and modeled for the profile likelihood ratio test of the second analysis. Finally, the first published results are reviewed in detail.
Thomas Shutt (Committee Chair)
Daniel Akerib (Advisor)
Corbin Covault (Committee Member)
Stacy McGaugh (Committee Member)
Harsh Mathur (Committee Member)
217 p.
Astrophysics; Chemical Engineering; Particle Physics; Physics; Radiation
Dark matter, direct detection, liquid xenon, gas chromatography, position reconstruction, dual-phase time projection chamber, radon progeny, profile likelihood ratio test, WIMP, WIMP-nucleon cross-section

Recommended Citations

Citations

  • Lee, C. (2015). MITIGATION of BACKGROUNDS for the LARGE UNDERGROUND XENON DARK MATTER EXPERIMENT [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1427482791

    APA Style (7th edition)

  • Lee, Chang. MITIGATION of BACKGROUNDS for the LARGE UNDERGROUND XENON DARK MATTER EXPERIMENT. 2015. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1427482791.

    MLA Style (8th edition)

  • Lee, Chang. "MITIGATION of BACKGROUNDS for the LARGE UNDERGROUND XENON DARK MATTER EXPERIMENT." Doctoral dissertation, Case Western Reserve University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1427482791

    Chicago Manual of Style (17th edition)

case1427482791
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© 2015, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.