Calculation of Distributions for Energy Imparted and Ionization by Fast Protons in Nanometer Sites

Results are presented for a Monte Carlo calculation of energy imparted and ionization in nanometer volumes by individual proton tracks. Representative frequency distributions for ionization are presented for 0.25- to 3-MeV protons passing through and near spherical sites of 1- to 200-nm-diameter unit density water in specified geometry. In addition, the radial dependences of the mean energy imparted and of the relative variance of the distributions are obtained as functions of the site diameter and of the ion energy.