Characterization and modeling of a low background HPGe detector

A high efficiency, low background counting setup has been made at TIER consisting of a special HPGe detector (similar to 70%) surrounded by a low activity copper+lead shield. Detailed measurements are performed with point and extended geometry sources to obtain a complete response of the detector. An effective model of the detector has been made with GEANT4 based Monte Carlo simulations which agrees with experimental data within 5%. This setup will be used for qualification and selection of radiopure materials to be used in a cryogenic bolometer for the study of Neutrinoless Double Beta Decay in Sn-124 as well as for other rare event studies. Using this setup, radio-impurities in the rock sample from India-based Neutrino Observatory (lNO) site have been estimated. (C) 2014 Elsevier B.V. All rights reserved