Recent improvements in neutron energy deposition calculations

At higher neutron energies calculations using the analytic method yield microdosimetric spectra in which the proton peak is narrower and shifted in peak energy when compared to experiment. This difference is usually attributed to the neglect of straggling in the calculation. In order to extend our calculational capability to this situation, we have written a Monte Carlo neutron energy deposition code which includes straggling of the energy depositions by charged particles in the sensitive volume. As a first consistency check, Monte Carlo calculations without straggling have been compared with the analytic method, and found to agree within the statistics of the Monte Carlo program. For thin sensitive volumes for which the Landau distribution should be appropriate, we are using the Monte Carlo code to calculate lineal energy (y) distributions with proton straggling included for energies up to 15 MeV. Comparisons to experiment will be made of the Monte Carlo method with straggling and the analytic method without straggling. One of the most interesting by products of this work is that it has shown us a relatively simple way to include Landau straggling in the analytic calculational method, greatly increasing the power of that method. We are now programming the inclusion of straggling into the analytic method code