Radiation damage of [formula omitted] pixelated CdZnTe due to high-energy protons

Abstract

Pixelated CdZnTe detectors are a promising imaging-spectrometer for gamma-ray astrophysics due to their combination of relatively high energy resolution with room temperature operation negating the need for cryogenic cooling. This reduces the size, weight, and power requirements for telescope-based radiation detectors. Nevertheless, operating CdZnTe in orbit will expose it to the harsh radiation environment of space. This work, therefore, studies the effects of 61MeV protons on 2×2×1cm3 pixelated CdZnTe and quantifies proton-induced radiation damage of fluences up to 2.6×108p/cm2. In addition, we studied the effects of irradiation on two separate instruments: one was biased and operational during irradiation while the other remained unbiased. Following final irradiation, the 662keV centroid and nominal 1% resolution of the detectors were degraded to 642.7keV,4.9%(FWHM) and 653.8keV,1.75%(FWHM) for the biased and unbiased systems respectively. We therefore observe a possible bias dependency on proton-induced radiation damage in CdZnTe. This work also reports on the resulting activation and recovery of the instrument following room temperature and 60°C annealing.