Radioactive contamination in Li2MoO4 crystals for the CUPID experiment

Establishing the radiopurity of Li2MoO4 crystals is a central requirement for the CUPID experiment, and pre-production CUPID Crystal Validation Runs (CCVR) are conducted to evaluate the effectiveness of the production chain by measuring the performance of the crystals as cryogenic calorimeters. In this framework, experimental energy spectra are compared with Monte Carlo (MC) simulations to identify radioactive contaminants and determine their origin, using a conservative procedure that provides 90% Confidence Level upper limits for different isotopes and contamination scenarios. The analysis of several crystals from a pre-production CCVR provides guidance for optimizing the crystal production process ahead of the full CUPID procurement.