LINEARITY WITH DOSE-RATE OF LOW-RESISTIVITY P-TYPE SILICON SEMICONDUCTOR-DETECTORS

Semiconductor detectors based on p-type silicon but with different doping levels have been investigated. The linearity response with dose rate (dose per pulse in a pulsed beam), the sensitivity drop and the sensitivity variation with temperature have been investigated after preirradiation, radiation damage, in different radiation qualities. It was shown that a p-type detector with a low doping level, high resistivity, showed a non-linear dose rate response if radiation damaged in a high energy photon beam, which contains neutrons. By increasing the doping level it was shown that a detector with a resistivity of 0.2 OMEGAcm stayed linear after preirradiation in radiation fields from high energy electrons, photons and protons. Other parameters did not show any changes of clinical importance at the different doping levels.