Energy deposition by nuclear interactions in microscopic volumes

A computer simulation has been developed which calculates the energy deposited in a small sensitive volume by nuclear interactions. A Monte Carlo approach is used. The energy deposited by the incident particles, by the cascade and evaporation particles, and by the residual nuclei from the interactions is calculated. The small sensitive volume can be embedded in a large volume, and energy deposited in the sensitive volume by interactions taking place in the large volume can be calculated. The nuclear model used in the simulation is shown to be in agreement with experiment and with other models. The predicted energy deposition spectra are shown to be in good agreement with results obtained by exposing silicon surface barrier detectors to proton beams at the Harvard Cyclotron. The recoiling residual nuclei were found to play a major role in the energy deposition in thin detectors. The simulation can be used to predict the soft error rate of microelectronic devices exposed to protons or neutrons. It will be particularly useful for devices flown in space, where protons are present in the radiation belts and are the most abundant component of the cosmic rays