The LZ Experiment and Purification of the Xenon Target Using Gas Charcoal Chromatography

LZ will be a 10 ton dual-phase xenon Time Projection Chamber (TPC) searching for WIMP dark matter via direct scattering from xenon nuclei.  In order to achieve the desired sensitivity, corresponding to a few events per year, we require an extremely radiopure environment.  Most of our backgrounds originate outside of the bulk xenon and are mitigated by xenon’s self-shielding properties combined with precision event position reconstruction and vetos.  A distinct challenge are background sources that are dissolved throughout the active region, such as Kr-85.  This talk will present an overview of LZ and describe our novel system for removing Kr-85 through gas charcoal chromatography. I’ll discuss the Kr removal R&D program that was recently completed at SLAC and give an overview of the production system we are building for LZ.