The three aims of this study are to prepare the Xenon Electron-recoil L-shell Analyzer
(XELDA) detector for its main dual-phase science run through hardware installation, effectively
simulate our detector to make comparisons with the data and confirm sufficient
shell resolution, and use gas-phase data to identify Rn-220 decay products. XELDA has
the capability to probe inner electron recoils, which are often assumed to create the same
detector response as outer shell recoils. This may be incorrect. If so, direct dark matter
detection experiments will need to account for the difference to avoid confusion between
inner shell electron recoils and the desirable nuclear recoils. A burst disk and new purifying
mode have been installed to increase detector sensitivity, and impurities in the detector
have been removed through heating and pumping. Simulation and data comparisons show
we are resolving the L- and M-shells. After running in gas mode and opening to a thorium
source (which decays into Rn-220), we are able to identify the Pb-212 decay, so it is possible
to estimate the intrinsic, uncontrollable background from the detector components in other
experiments by searching for similar daughters. The main difference between the Rn-220
and the Rn-222 decay chain (in other experiments) is that Rn-220 daughters have longer
decay times.
