Research on the proton-induced radiation damage of pixelated CdZnTe detectors for space applications

High-performance pixelated CZT detectors that achieve 3D position sensitivity are promising candidates for use in Compton imaging telescopes. We proposed to use pixelated CZT detectors in the MeV Astrophysical Spectroscopic Surveyor (MASS), which is a large area Compton telescope. Nevertheless, the presence of high-energy protons in space can lead to radiation damage in pixelated CZT detectors, causing their performance to degrade gradually. Using non-ionizing energy loss (NIEL), this study develops a method that quantitatively evaluates the radiation damage of detectors in space. To verify the method, this study irradiated two \(2\times 2\times 1\text { cm}^3\) pixelated CZT detectors with 100 MeV protons at fluences ranging from \(3\times 10^7\text { p}^+/\text {cm}^2\) to \( 3\times 10^9\text { p}^+/\text {cm}^2\) under two bias sets. When the proton fluence reaches \(3 \times 10^9 \text { p}^+/\text {cm}^2\), the energy resolution of the detectors significantly deteriorates to \(3.8\%\) at 511 keV (FWHM/E), even after post-correction. Finally, this study provides engineering considerations for their application in space.