Speaker
Kelly Stifter
(Stanford University)
Description
LZ is a next generation dark matter search experiment designed to significantly extend our sensitivity to WIMP dark matter candidates. At the core of the LZ design is a dual-phase Xe time projection chamber (TPC) with a 7 ton active mass. To observe signals from low-energy nuclear recoils, including WIMP-xenon scatters, four custom-woven wire-mesh grids of 1.5m diameter establish strong electric fields in the TPC to drift ionization electrons across the volume and extract them from the liquid surface. As a result of the high electric fields, dielectric breakdown between high voltage surfaces and spurious electron emission from regions of high surface fields are major concerns. To mitigate these risks, an R&D program exploring design geometry in high field regions, cleanliness procedures, and surface treatments has been carried out using a comprehensive suite of three mid-scale dual- and single-phase xenon detectors. This presentation will cover the design and construction of the LZ grids, and several aspects of the high voltage performance seen in the testing program.
Primary author
Kelly Stifter
(Stanford University)