Abstract: A process for producing an encapsulated detector operating in an ultra high vacuum (UHV) for gamma (.gamma.) spectroscopy, wherein a detector is placed into a detector chamber portion of a detector containment pot and a lid is placed into the containment pot and both are joined by electron beam welding under vacuum at their top in such a way, that the detector is not exposed to excessive heat and that the vapors generated during welding are condensed before they can reach the detector chamber, whereby a detector capsule capable of maintaining an ultra high vacuum can be produced.

Abstract: In a capsule for a detector operating in an ultra high vacuum suitable as a gamma radiation spectrometer, there is provided a detector chamber in which the detector is mounted and a getter chamber in which a getter element is mounted and the getter chamber is separated from the detector chamber by a thermal protection structure to prevent heating of the detector when the getter element is heated for conditioning. The getter element serves to maintain an ultra high vacuum in the detector chamber over a long period of operation.