Black-body approximation to the continuous X-ray spectra

The shape of the continuous X-ray spectrum is approximated by the Planck’s distribution law for black-body radiation. The energy distribution of continuum X-rays produced by a bombardment of 30 kV electron beam onto a gold target is reproduced by the black-body radiation at a temperature of 10⁷ K. The continuous spectrum measured when the incident electron energy varies in the range 30, 20, 10, and 5 kV, and for different target elements such as gold, iron, and carbon, are again reproduced in their absolute intensity scale. Consequently, it is speculated that the Stefan–Boltzmann's law as well as the Wien's displacement law also hold for the continuum X-ray radiation.