Fig. 6From: PENELOPE/PRIMO-calculated photon and electron spectra from clinical acceleratorsComparison of the PENELOPE/PRIMO electron spectra for Varian beams of 6, 12 and 18 MeV with those calculated by Ding and Rogers [15], dotted histograms. All the spectra are normalized to their respective integral. The fluence-weighted mean energies of each spectrum are indicated in the inset. Note that the two linacs were not identical (see text)Back to article page