Speaker
Description
PandaX-20T is a next-generation liquid xenon detector for rare-event searches, with stringent requirements on radiopurity and background control. We present the ongoing low-background effort for PandaX-20T, including material screening, development of new low-background materials and detector components, krypton assay, radon-related surface contamination control, and detector background estimation. Complementary techniques such as HPGe gamma spectroscopy, ICP-MS, krypton assay, and radon emanation measurements are used to characterize radioactive impurities in candidate materials and components. Surface treatment and cleaning procedures are developed to suppress radon-related contamination. The assay results are incorporated into a detailed background model and Monte Carlo simulations to evaluate gamma and neutron backgrounds from major detector subsystems. These efforts provide essential input for material selection, component development, detector optimization, and the projected background performance of PandaX-20T.