Background suppression in the COSINUS experiment: Active muon veto and radiopure materials selection

For over twenty-five years the DAMA/LIBRA experiment has reported an annual modulation signal that is consistent with a dark matter explanation. This is, currently, in tension null results observed by other searches utilize different target detectors. The COSINUS will perform model-independent cross-check of result using same material, NaI crystals, operated as scintillating calorimeters. By measuring both temperature and light crystals be able to distinguish between electron nuclear recoils on event-by-event basis. However, background events induced cosmic-rays, environmental radioactivity or intrinsic contamination materials used crystal, shielding infrastructure can pose issue any analysis must fully understood. We report status development simulation for active water Cherenkov muon veto, well beginning radiogenic material screening.