RESPONSE OF SI DETECTORS TO ELECTRONS, DEUTERONS AND ALPHA-PARTICLES

The response of silicon detectors to conversion electrons in the decay of Cd-109, Pa233 and Cs-137, to deuterons in the energy range 35-440 keV from a Van de Graaff accelerator and to alpha particles from a mixed Pu239, Am241, Cm244 source has been measured. The results were found to be in agreement with the model proposed by Lennard et al. (1986) which describes the nonlinear detector response in particular for the case of light ions. For electrons, the nonlinearity was found to be negligible within experimental uncertainties. For deuterons the nonlinearity observed in Rutherford-backscattering measurements at low energies was used to accurately measure the window thickness of the detectors. For alpha particles in Si it has been confirmed that the energy required to create an electron-hole pair depends on the stopping power. Our value for the nonlinearity parameter k = 2.8+/-0.3 nm/electron-hole pair is larger than the one which was originally proposed.