Characterization of CaWO4 scintillator at room and liquid nitrogen temperatures

The properties of CaWO4 (CaWO) crystals in gamma-spectrometry were studied at room and liquid nitrogen(LN2) temperatures. Two small samples of 10 x 10 x 4 mm(3) and 10 x 10 x 8 mm(3) size were tested, coupled to a Photonis XP3212 photomultiplier at room temperature and a large area avalanche photodiode at LN2 temperature. Light pulse shape and light output at room and LN2 temperatures were measured. Energy resolution and non-proportionality of the CaWO response versus gamma-ray energy were studied and compared with those of small BGO and CdWO4 crystals to discuss further the origin of the intrinsic resolution of undoped scintillating crystals. A high light output of 4800 +/- 200 phe/MeV and a good energy resolution of 6.6 +/- 0.2% for 662 keV gamma-rays from a (CS)-C-137 source were measured for the small samples coupled to the XP3212 photomultiplier. (c) 2005 Elsevier B.V. All rights reserved.