Radiation hardness of high resistivity CZ Si detectors after gamma, neutron and proton radiations

High resistivity CZ Si detectors have been irradiated by gamma, neutrons, and protons to various doses/fluences, along with control FZ Si detectors. It has been found that 1) for gamma radiation, CZ Si detectors behave similarly to the HTLT oxygenated FZ Si detectors: no SCSI and there is a build-up of positive space charges. The rate for this build-up is much higher than that for the HTLT oxygenated Si detectors, and is proportional to the oxygen concentration; 2) for neutron radiation, there is little difference between CZ and control FZ (CFZ) silicon detectors: SCSI is observed for both CZ and CFZ Si detectors, and the introduction rate of deep acceptors (beta) for CZ Si detectors is slightly less than that for CFZ Si detectors; and 3) for proton radiation (10 MeV and 20 MeV), although the SCSI is also observed for CZ Si detectors, the 1 MeV neutron-equivalent SCSI fluence is about 3 times higher than that of CZ Si detectors irradiated by neutrons, and beta is about 1/2 of that for HTLT oxygenated Si detectors. High resistivity CZ Si is therefore found behaving similarly to the HTLT oxygenated Si detectors, and even more radiation hard to charged particles.