Measurement of primary bremsstrahlung spectrum from an 8-MeV linear accelerator

The bremsstrahlung spectrum from an 8-MeV linear accelerator has been measured using a NaI(T1) spectrometer system. The spectrum shows a low-energy cutoff at 0.4 MeV and the maximum photon energy to be approximately 6% greater than the nominal energy. The maximum emission of energy fluence was 1.6 and 1.8 MeV for measured and calculated values, respectively. The fast neutron dose in the photon beam was approximately 0.09% of the x-ray dose. The weighted mean energy was 2.3 MeV, measured value, and 2.4 MeV, calculated value.