Radiation damage in large-volume n- and p-type high-purity germanium detectors irradiated by 1.5 GeV protons

Excellent energy resolution makes germanium detectors prime candidates for gamma-ray spectroscopy in space missions. The authors present a study of several large-volume n-type and p-type high purity germanium (HPGe) detectors that were damaged by 1.5 GeV protons and examine their performance as function of fluence, operating and anneal temperature, and time. N-type detectors exhibit essential advantages for space applications over p-type detectors. Annealing at about 110 K for both detector types was observed as well as resolution transients up to 134 K. They discuss the observed radiation effects with respect to existing models and show their limitations