CdWO/sub 4/ crystal in gamma-ray spectrometry

The properties of CdWO/sub 4/ (CWO) crystals in gamma spectrometry were studied. Several small samples of 10/spl times/10/spl times/3 mm size, typically used in CT X-ray detectors, were tested and then compared to the performance of a larger crystal of 20 mm in diameter and 20 mm in height. The light output, energy resolution, and non-proportionality of the CWO response versus gamma-ray energy, were measured and compared with those of a small BGO to discuss further the origin of the intrinsic resolution of pure undoped scintillating crystals. A high light output of 6500 /spl plusmn/ 200 phe/MeV and a good energy resolution of 6.6 /spl plusmn/ 0.2% for 662 keV gamma rays from a /sup 137/Cs source were measured for the small samples coupled to an XP3212 photomultiplier. Common non-proportionality curves and consequently common intrinsic resolutions of small CWO and BGO suggest that they represent fundamental characteristics of the heavy oxide scintillating material themselves.