Fast neutron damage of a pixelated CdZnTe gamma ray spectrometer

This study describes the damage to a pixelated 1cm x 1cm x 1cm CdZnTe detector caused by fast neutrons in the energy range 1–7 MeV. Measurements of electron μτ product were performed before and after irradiation and after thermal annealing. Spectroscopic information was acquired with a ¹³³Ba gamma source. Before irradiation, sharp peaks were observed for the 133Ba lines, with combined pixel energy resolution for the 356 keV line of 1.6 % FWHM. After irradiation, clear deterioration of the spectral response is observed, with energy resolution of the 356 keV line of about 6 % FWHM. After thermal annealing, the spectral response shows significant recovery, with combined energy resolution of 2.1 % FWHM. We successfully simulate these results with a theoretical model. It is concluded that the fast neutrons cause displacement damage in the lattice of the bulk CdZnTe material..