Properties of CdWO<inf>4</inf> and ZnWO<inf>4</inf> at liquid nitrogen temperature

Abstract

Tο samples of 10 mm diameter and 10 mm height CdWO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> (CdWO) and ZnWO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> (ZnWO) scintillators were studied at room (RT) and liquid nitrogen (LN <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> ) temperature. At room temperature the crystals were coupled to a Photonis XP3212 photomultiplier. During experiments in liquid nitrogen a Large Area Avalanche Photodiode (LAAPD) was used as a photodetector. Measurements of light output, non-proportionality of the light yield and intrinsic resolution as a function of gamma-ray energies were performed at both temperatures. The non-proportionality for the two crystals, likely CaWO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> , reveals temperature dependence, to reach the same values at LN2 temperature. Intrinsic energy resolution for both crystals was also changed at LN <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> comparing to the data collected at RT. The intrinsic energy resolution was improved below 100 keV and deteriorated for higher energies.