Study on the Energy Resolution Degradation at Low Cathode Bias for the Pixelated CdZnTe Detectors

For CdZnTe detectors, the energy resolution usually improves at a higher cathode bias. However, there are many practical benefits to operate pixelated CdZnTe detectors at lower cathode biases. This study explores the factors limiting the energy resolution at lower cathode bias. Measurements using the digital ASICs are presented and discussed. Effects of trapping, material defects, shaping and data sampling are investigated. Methods to mitigate the energy resolution degradation are proposed.