SIMULTANEOUS COUNTING OF ALPHA-RAYS, BETA-RAYS AND GAMMA-RAYS WITH PHOSWICH DETECTORS

Phoswich detectors for simultaneous counting of alpha, beta and gamma rays have been developed, which were prepared by combining two or three scintillators, ZnS(Ag), NE102A and/or BGO or NaI(TI), with different rise times from each other. In order to adjust the pulse height ascribed to each scintillator within a dynamic range, a sheet of Au-Mylar was used, if necessary, as an optical neutral density filter for lowering the transmittance of scintillation of the ZnS(Ag). Characteristics of these phoswiches were examined by a pulse shape discrimination technique. Excellent discrimination among the radiations was attained for the prepared phoswiches.