Charge-Deposition Spectra in Thin Slabs of Silicon Induced by Energetic Protons

Pulse-height spectra were measured in thin slabs of silicon (2.4 to 97 μm) exposed to protons incident at energies from 25 MeV to 158 MeV at the Harvard Cyclotron. The data is compared to the predictions of the simulation model of Farrell and McNulty and shown to be in good agreement over the range of detector thicknesses and proton energies tested. The probability of depositing a given energy in an event was found to decrease exponentially with the amount of energy to be deposited. This probability, corresponding to the negative slope on a semilogarithmic plot depends on the dimensions of the sensitive volume and the energy of the incident proton.