ENCAPSULATION OF GERMANIUM DETECTORS FOR SPACE-FLIGHT

A hermetic enclosure for a high-purity germanium detector was develope d as part of the detector assembly for the Transient Gamma-Ray Spectro meter flown on the WIND satellite. High G forces during launch (simila r to 100G), long term stability (lifetime of at least 5 years), passiv e cooling and low energy photon detection were critical parameters add ressed. These design parameters dictated rigid containment of the dete ctor and the selection of enclosure materials, hermetic high voltage a nd signal feedthroughs, electrical contacts to the detector and enclos ure seals. Sealing of the germanium detector within a valveless hermet ic enclosure was achieved with a custom vacuum bell-jar press equipped with a vacuum isolated hydraulic ram. Both vacuum and nitrogen gas fi lled encapsulations (pressurized to 2 atmospheres) were examined; nitr ogen gas filled encapsulations were more rugged.