PERFORMANCE OF A GE-BGO COMPTON-SUPPRESSION SPECTROMETER AND ITS APPLICATION TO PHOTON-ACTIVATION ANALYSIS

A Compton-suppression spectrometer, consisting of a pure Ge detector a nd EGO shield detectors is described. A cylindrical symmetry type of t he shield detector configuration, with the Ge detector inserted on the symmetry axis, has been designed. The Compton-suppression factor is 6 .0 for the photopeak of Co-60 at 1332.5 keV. The peak-to-Compton ratio for the peak is 42:1 when the BGO detectors are used as a passive shi eld only, and is 250:1 in the suppression mode. Photon activation anal ysis with this detector has been made for the determination of trace e lements in a bulk dysprosium sample. The signal-to-noise ratio for det ecting trace elements in the sample has been improved by a factor from 1.3 to 3.1 by Compton suppression compared with that obtained in the non-suppression mode.