Simulation Of Cosmogenic Activation In Germanium For Rare Event Searches

Experiments looking for rare events like the direct detection of dark matter particles orthe nuclear Double Beta Decay are operated in deep underground locations, to suppress orvery effectively reduce the effect of cosmic rays; but cosmogenic activation produced at sealevel in detectors and other materials can become a serious hazard for them.The biggest amount of cosmogenic activity is expected to be produced duringtransportation of either enriched material or already grown crystal. germanium is veryfrequently used in this kind of experiments requiring an ultra-low radioactive background andtherefore has been chosen as activation targets in this work. First, the cross section forrelevant induced long-lived radioactive isotopes has been estimated by the GEANT4. Then,the corresponding rates of production of the nuclides in enriched (86%76Ge and14%74Ge)germanium has been evaluated. Comparison of the obtained activation yields with all theknown previous results (based either on calculations or experiments) has allowed drawingconclusions on the general methodology for evaluating cosmogenic activation.