Encapsulation of germanium detectors for space flight

A hermetic enclosure for a high-purity germanium detector was developed as part of the detector assembly for the Transient Gamma-Ray Spectrometer flown on the WIND satellite. High G forces during launch (/spl sim/100 G), long term stability (lifetime of at least 5 years), passive cooling and low energy photon detection were critical parameters addressed. These design parameters dictated rigid containment of the detector and the selection of enclosure materials, hermetic high voltage and signal feedthroughs, electrical contacts to the detector and enclosure seals. Sealing of the germanium detector within a valveless hermetic enclosure was achieved with a custom vacuum bell-jar press equipped with a vacuum isolated hydraulic ram. Both vacuum and nitrogen gas filled encapsulations (pressurized to 2 atmospheres) were examined; nitrogen gas filled encapsulations were more rugged.