Correlation between deep-level parameters and energy resolution of p-type high purity Ge γ-detectors

A physical basis is presented for the previously reported correlation between deep levels in p-type high purity germanium and the energy resolution of corresponding γ-detectors. Taking account of re-emission of trapped holes at 77 K it is shown that effective hole traps are deeper than about Ev+0.07 eV. Slowly re-emitting traps may become saturated during detector operation. The detector resolution criterion L ≤ 2 keV is found to correspond with an upper limit of 4.5 x 109 cm-3 for the total active copper density. This density criterion is shown to be a reliable basis for the routine DLTS characterisation of high purity germanium production. (orig.)