Evaluation of cosmogenic activation of copper and germanium during production in Jinping Underground Laboratory

Intrinsic radiation of materials is one of the major backgrounds for many rare-event search experiments.Thus,the production of pure materials in an underground laboratory is a promising approach for eliminating cosmogenic radionuclides.In this paper,we demonstrate a procedure to evaluate the yields of cosmogenic radionuclides in copper and germanium in the second phase of the China Jinping Underground Laboratory.Our results show that for copper and germanium materials,the largest cosmogenic background comes from;H and;Co,and;H and;Ge,respectively,which all have yields on the order of 10;kg;day;.The corresponding radioactivities after 90 days pf exposure underground are estimated to be lower than 10;μBq kg;.