Speaker
Description
We present the crystal xenon time-projection chamber (CXe TPC), a novel particle detector technology, as a proposed future upgrade to current liquid xenon (LXe) TPC experiments and as a standalone next-generation detector. A sensitivity-reducing hurdle for LXe-based dark matter searches is radon decay-chain betas, which produce the dominant background. Foundational tests using a sub-kg CXe TPC have shown upwards of 500x reduction in the radon background via radon exclusion across the crystal boundary. Additionally, increased electron drift speed is observed, which may lead to a reduced rate of accidental coincidence backgrounds that dominate the low-energy regime. Both of these properties of CXe help to improve sensitivity over LXe, while maintaining the general effectiveness of LXe as a detector medium. In this presentation, we discuss measurements of scintillation signals in CXe at the 10-kg scale, their dependence on crystal growth rate and other parameters, and a model of crystal growth up to the tonne-scale.