Radiation effects in CdZnTe gamma-ray detectors produced by 199-MeV protons

Larry S. Varnell; William A. Mahoney; Ethan L. Hull; Jack F. Butler; Ahsan Wong

doi:10.1117/12.254014

18 October 1996 Radiation effects in CdZnTe gamma-ray detectors produced by 199-MeV protons

Larry S. Varnell, William A. Mahoney, Ethan L. Hull, Jack F. Butler, Ahsan Wong

Proceedings Volume 2806, Gamma-Ray and Cosmic-Ray Detectors, Techniques, and Missions; (1996) https://doi.org/10.1117/12.254014
Event: SPIE's 1996 International Symposium on Optical Science, Engineering, and Instrumentation, 1996, Denver, CO, United States

Abstract

Many future space missions will use cadmium zinc telluride (CdZnTe) gamma-ray detectors because their operation at room temperature makes compact, lightweight detector systems possible. Even though instruments for space using CdZnTe detectors have already been built, the effect of the high- energy particle space environment on these detectors has not been measured. To determine the effect of energetic charged particles on these detectors, we have bombarded several CdZnTe detectors with 199 MeV protons at the Indianan University Cyclotron Facility. Planar detectors of area 1 cm² and thickness 2-3 mm from both eV products and Digirad were irradiated, along with a 2 multiplied by 2 array of proprietary design from Digirad. Using standard gamma-ray sources, the response of the detectors was measured before and after bombardment in steps up to fluences of 5 multiplied by 10⁹ p cm^-2. Significant effects from the proton irradiation were observed in the gamma-ray spectra. In particular, the peak positions of the lines in the spectrum were shifted downward proportional to the fluence. The explanation is almost certainly the production of electron traps by the high energy proton interactions, resulting in a decrease of the mobility-lifetime ((mu) (tau) ) product of the electrons. Calculations were made to model the effect of a decrease in electron trapping length on the spectrum.

Citation Download Citation

Larry S. Varnell, William A. Mahoney, Ethan L. Hull, Jack F. Butler, and Ahsan Wong "Radiation effects in CdZnTe gamma-ray detectors produced by 199-MeV protons", Proc. SPIE 2806, Gamma-Ray and Cosmic-Ray Detectors, Techniques, and Missions, (18 October 1996); https://doi.org/10.1117/12.254014

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