Radiation effects in silicon detectors processed on carbon and oxygen-rich substrates

Radiation hardness results of silicon detectors fabricated on bulk float-zone (FZ) material enriched either by carbon or by oxygen are reported. The detectors were irradiated by nuclear reactor neutrons, by 24 GeV/c protons and by 192 MeV pions. It has been shown that the leakage current increases with fluence equally in all silicon detectors under study, regardless of the oxygen or carbon concentrations. The variations in the space-charge density were found to be very different in the oxygen and carbon-enriched materials in the case of irradiation by charged particles, yet rather similar in case of neutrons.