Figure 8.

Absorbed dose in Gy per primary scored in each volume from Fig. 1 for the 1.25 MeV photons (a) and 150 MeV protons (d) calculated with penh and geant4/topas using the physics lists g4em‐standard_opt3 and g4em‐standard_opt4. In (b) and (e), the deviations relative to penh are shown. The statistical uncertainties of the absolute absorbed doses are smaller than the symbol size. The statistical uncertainties represented by bars in panel (b) and (e) correspond to one standard deviation. (c) The results for $f_{Q_0}$ factors for 1.25 MeV photons; (f) the results for $f_Q$ factors for 150 MeV protons. The statistical uncertainties represented by bars correspond to one standard deviation. [Color figure can be viewed at http://www.wileyonlinelibrary.com/]