Fig. 3From: PENELOPE/PRIMO-calculated photon and electron spectra from clinical acceleratorsComparison of the PENELOPE/PRIMO photon spectra for Varian beams of 6 and 15 MV with those calculated by Mohan et al. [10], dashed histograms, and Sheikh-Bagheri and Rogers [13], dotted histograms. All the spectra are normalized to their respective integral. The fluence-weighted mean energies of each spectrum are indicated in the insetBack to article page