A Position-Sensitive Liquid Xenon Time-Projection Chamber for Direct Detection of Dark Matter: The XENON10 Experiment Sorensen, Peter F creator 2008 x, 195 p. born digital Thesis (Ph.D. -- Brown University (2008) Gaitskell, Richard Director Robert, Lanou Reader Dell'Antonio, Ian Reader Brown University. Physics sponsor theses Recent astrophsyical observations indicate that about 23% of the matter in the universe exists as non-luminous, non-baryonic dark matter. General thermodynamic arguments suggest that if an as-yet undiscovered weakly interacting particle were in thermal equilibrium in the early universe, it could have a cosmologically interesting relic abundance today. Dark matter particles are predicted to have collapsed into isothermal halos on a galactic scale. Minimal super-symmetric extensions of the standard model predict the existence of a stable particle with a mass in the range 10-1000 GeV c^-2, and a an interaction cross section with ordinary matter σχ < 10^-36 cm². For the past two decades, numerous experiments have been deployed with the aim of direct or indirect detection of dark matter. XENON10 is a direct-detection liquid Xe experiment, with event-by-event 3D position reconstruction. Since dark matter does not interact electromagnetically, it's signature in a Xe detector is expected to be a low-energy nuclear recoil. Particle interactions in Xe create scintillation light (<em>S</em>1) and ionization. The ionization is drifted across the active Xe target and converted into a proportional scintillation signal (<em>S</em>2) by an external electric field. The ratio y = log10(<em>S</em>2/<em>S</em>1) is larger for β and ɣ background events than for nuclear recoils, as determined by neutron calibration data. This allows event-by-event discrimination of background from the expected signal. In 2007 XENON10 eclipsed CDMS II as the most sensitive direct-detection experiment, excluding the existence of particle dark matter with a cross-section (normalized to a single nucleon) σχ > 10^-43 cm² at a particle mass of 100 GeV c^-2 (90% C.L.). Liquid Xe technology is extremely promising since it is easily scaled to larger target mass, which will allow greater sensitivity to particle dark matter interactions. I discuss the XENON10 detector, deployment, operation, analysis and dark matter exclusion results. I also present a new method to determine the light yield of Xe for nuclear recoils, which is essential for calibrating the nuclear recoil energy scale and understanding the detector threshold. WIMP dark matter liquid Xe Dark matter (Astronomy) RPB 20110926 engEnglish 10.7301/Z0V1231M In CopyrightCollection is open for research.dissertations