Performance of common-grid pixelated CZT detector with different array geometries

Abstract

A 4 × 4 common-grid pixelated CZT detector with four different array geometries has been designed and fabricated. The impact of small pixel effect, guide effect of the steering grid and edge effect on detector performance has been investigated. Both the weighting potential and the real electric field distributions have been calculated for better understanding the charge induction and collection. Results show that with constant pixel pitch, smaller anode pixel suffers from serious charge loss in volume and surface layer between anode pixels and steering grid. The small pixel effect is not strong enough to remove hole trailing for lager anode pixel. A relative high potential difference between anode pixels and steering grid leads to sufficient charge collection resulting in a better detector performance, especially for smaller anode pixels. In addition to edge and corner effects due to faulty or imperfect fabrication of the detector, the weighting potential distribution difference is an inherent physical effect that alter the profile of the induced signals in edge and corner pixels.