Photon energy distribution of some typical diagnostic x‐ray beams

A high‐purity germanium spectrometer system was used to determine primary x‐ray spectra over the 45–90‐kVp region. Methods were devised for producing and examining spectra simulating diagnostic conditions without operating the x‐ray generator at high current levels. The techniques used to correct the experimental data and produce a photon fluence spectrum are discussed. The results, presented graphically and in tables, have been normalized to yield the relative number of photons per 2‐keV interval. Methods for converting a normalized spectrum into a photon fluence spectrum that will produce an exposure of 1 R are presented. The analytical model and procedures used to calculate the K ‐escape fraction are discussed.