On the Origin of Leakage Current in Ge(Li) Gamma-Ray Detectors

Hole-electron pair generation in Ge(Li) γ-ray detectors due to thermal radiation from the cryostat outer casing is suggested as an often overlooked source of detector leakage current. Thermal-radiation-induced currents of the order of 10-9A are estimated for a typical large coaxial detector at 77°K when the cryostat outer casing is at 300°K.