CdWO/sub 4/ crystal in gamma-ray spectrometry

The properties of CdWO₄ (CWO) crystals in gamma spectrometry were studied. Several small samples of 10times10times3 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 nonproportionality 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 6500plusmn200 phe/MeV and a good energy resolution of 6.6plusmn0.2% for 662 keV gamma rays from a ¹³⁷Cs source were measured for the small samples coupled to an XP3212 photomultiplier. Common nonproportionality curves and consequently common intrinsic resolutions of small CWO and BGO suggest that they represent fundamental characteristics of the heavy oxide scintillating material themselves