Figure 8.

The combined effects of Doppler broadening, detector spatial resolution, and detector energy resolution on the cumulative distribution of gamma DCA values for a simulated CC detecting secondary gamma radiation during proton therapy. (a) The effects for several detector material and resolution combinations. (b) The difference in the distributions for high energy, >2.0 MeV, and low energy, < 2.0 MeV, incident gammas using a CC with 0.5 mm spatial resolution and δ(E) scaled to 1. The distributions of all detected gammas and only gammas within ±0.1 MeV of a known PG energy are shown as well. The detector energy resolutions δ(E) were calculated from the energy resolution formula for the corresponding material, δ_HPGe(E) and δ_CZT(E) for HPGe and CZT, respectively.