Calculated Bremsstrahlung Spectra from Thick Tungsten Targets

The bremsstrahlung energy distribution from a thick tungsten target is calculated from the Sommerfeld and Born-approximation thin-target formulas, taking into account electron energy losses, electron backscatter losses, and photon attenuation in the target. Over-all agreement with measurement is 20% in the 12-100-keV energy range, increasing to 50% at 300 keV. Semiempirical expressions are developed that give 20% over-all agreement with measurement in the 12-300-keV energy range.