Characteristics of Large Intrinsic Germanium Detectors Operated at Elevated Temperatures

The operational characteristics of two large (25 and 75 cm3, coaxial) intrinsic germanium detectors have been investigated as a function of temperature in order to establish definitive base lines and design criteria for satellite-borne spectrometer systems. The selection of a cooling system and the optimization of the design are critically dependent upon the acceptable temperature limits for the operation of a germanium detector. To establish the usable range for operation we have studied the temperature dependence of critical parameters such as the energy resolution, pulse height and reverse current. The data, although based on only two detectors, indicate the possibility of operating large intrinsic detectors at temperatures significantly higher than that observed for Ge(Li) detectors of comparable size.