Stability and characteristics of large CZT coplanar electrode detectors

The single polarity charge sensing method based on coplanar grid electrodes has demonstrated promising results on CZT detectors having volumes of simi lar to1 cm(3). This paper presents. the performance of two coplanar grid CZ T detectors having dimensions of 1.5 x 1.5 x 1.0 cm(2), among the largest C ZT spectrometers that have been reported. Energy resolutions of 2.3 % and 2 .0 % full-width half-maximum were obtained on the two detectors at 662 keV using simple analog techniques. Further improvement is achievable with dept h sensing and digital pulse processing techniques. Other detector character istics, critical to practical application of these devices, are reported he re. This includes the stability of detector response over a period of sever al months and the variation of detector performance in environments having high gamma radiation fluxes and a range of counting rates.