Fig. 2From: Using field size factors to characterize the in-air fluence of a proton machine with a range shifterMeasured FSFs at five positons (isocenter, ±10 cm and ±20 cm) for the proton energy of 121 MeV, and at the isocenter plane for the proton energies of 80.3 Mev and 175.6 MeVBack to article page