Lineal energy as a function of site size for HZE radiation.

Monte Carlo calculations have been used to estimate the frequency and magnitude of energy deposition events produced by delta rays originating with high atomic number, high-energy, primary particles. The results show that the spectrum of delta rays incident on small targets is relatively insensitive to primary particle velocity or distance to the primary track. They suggest that measurements of energy deposition in different size sites can be used to characterise the velocity of the incident particle.