Radiation hardness studies of CdTe and HgI2HgI2 for the SIXS particle detector on-board the BepiColombo spacecraft

We report of the radiation hardness measurements that were performed in the developing work of a particle detector on-board ESA's forthcoming BepiColombo spacecraft. Two different high-ZZ semiconductor compounds, cadmium telluride (CdTe) and mercuric iodide (HgI2), were irradiated with 22 MeV protons in four steps to attain the estimated total dose of 1012p/cm2 for the mission time. The performance of the detectors was studied before and after every irradiation with radioactive 55Fe source Mn Kαα 5.9 keV emission line. We studied the impact of the proton beam exposure on detector leakage current, energy resolution and charge collection efficiency (CCE). Also the reconstructive effect of annealing on radiation induced damage was tested for CdTe detector.