Measurement of the Fano factor for protons on silicon

Abstract The Fano factor for protons has been measured for silicon with a surface barrier semiconductor detector at 87 K over the energy range of E p = 0.989–4.537 MeV. The fwhm of peaks in the spectra observed were corrected for effects of plasma and of charge collection. As a result of the analysis, the value of the Fano factor was obtained as 0.16±0.04. However, the value of the corrected fwhm at E p = 0, estimated by extrapolation, cannot be accounted for by the effect of atomic collision.