A HIGH SOLUTION GAMMA SPECTROMETER WITH A BORE-HOLE GERMANIUM DETECTOR

Description is given for a high-volume lithium-drifted bore-hole germanium detector and the vacuum chamber in which it is operated. The detector is especially suited for investigations of low gamma-active samples as often arising in the fields of medicines, biology, and radiochemistry. The germanium crystal is built into a vacuum-tight casing on which an ion-spray-pump is welded, and by which the detector casing can further be evacuated in case of necessity. Detector canning is layed out to permit an easy mounting of the bore-hole detector into the measuring equipment. Moreover, it can easily be transported, and in the state of non-operation easily be stored in dry ice. The detector casing has given evidence for its stability and operation safety. The detector itself is operated in a vacuum chamber which permits to load the detector in the vacuum with the probes destinated for investigations. Operation of the vacuum chamber succeeds full-automatically so that no mistakes in maintenance may occur. During probation run of several weeks it was shown that the equipment works in full operation safety. Measrements with a probe which had an activity of approximately 0.47 nCi resulted in a resolution of nearly 5 keV (fwhm) with reference to the 662 keV 137Cs-line. The vacuum chamber has been layed out to permit utilization also for other experiments with semiconductor detectors. © 1969.