Efficient temperature corrections for gamma-ray energy reconstruction in 3-D position-sensitive CdZnTe detectors

Maintaining good energy resolution in 3-D position-sensitive cadmium zinc telluride (CdZnTe) detectors without temperature regulation is desired in field operations to lower power consumption. This requires several calibration measurements at various ambient temperatures. However, required calibration times and storage space for calibration data increase linearly with working temperature range. In this experiment, gamma-ray interactions were measured by 3-D, position-sensitive CdZnTe detectors read out via VAD_UM v2.2 ASICs at various ambient temperatures. Physical causes of changes in detector behavior were studied. A proposed method to reconstruct events using only one complete calibration measurement, and several faster measurements at different ambient temperatures is discussed. Calibration data estimated using the proposed method showed almost identical performance compared to measured calibration data for measurements for various ambient temperatures at equilibrium. The paper also discusses experimental results that showed good resolution in 3-D CdZnTe detector systems can be achieved even if temperature regulation is fully discarded.