Thesis and Dissertation Defenses
MiniCLEAN Dark Matter Experiment
Presented by Jui-Jen Wang
Particle Dark Matter is a hypothesis accounting for a number of observed astrophysical phenomena such as the anomalous galactic rotation curves. From these astronomical observation, about 23% of the universe appears to consist of dark matter. Among the possible candidates for dark matter, a plausible one is a Weakly Interacting Massive Particle (WIMP). A particle with the required properties is beyond the standard model of particle physics. The MiniCLEAN experiment is single-phase liquid-argon detector instrumented with 92 photomultiplier tubes placed inside the cryogenic liquid with 4-pi coverage of a 500 kg (150 kg) target (fiducial) mass. For this experiment, PMT stability and calibration are essential. In-situ optical calibration monitors the PMT stability and the energy calibration. We use LEDs to provide a real-time single photon calibration. The naturally occurring Ar-39 beta-emitting isotope provides another way to calibrate the detector. In data taken in cold gas during liquid argon filling we have measured a triplet lifetime (~ 3.5 us), the longest ever measured and confirming a very high argon purity. This long triplet lifetime in gaseous argon provides improved pulse shape discrimination (PSD) that could be exploited an a possible future gaseous dark matter detector. Low density and large recoil lengths might have other benefits as well for dark matter searches.
10:00 am, Tuesday, September 12, 2017
PAIS-2540, PAIS
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