Fig. 7From: PENELOPE/PRIMO-calculated photon and electron spectra from clinical acceleratorsComparison of 6 MeV electrons depth-dose distribution for a 15 cm × 15 cm field, obtained from the PSF (solid line) with those obtained using the spectrum plus an added 100 cm air filtration (dots), 100 cm of vacuum filling the space between the source and the phantom (long dashes), and 95 cm vacuum followed by 5 cm of air (short dashes). The corresponding values of R50 and Rp are given in the insetBack to article page