Absorption Analysis of X-Ray Spectra Produced by Beryllium Window Tubes Operated at 20 to 50 Kvp

It has been shown that absorption analysis can be employed to determine the spectrum of an x-ray beam containing characteristic x-ray lines superimposed on the continuous spectrum. In order to analyze such beams it is necessary to collect absorption data on a second tube, identical to the first except for target material, and operated at the same voltage and current. The method was used to determine the spectra of four different x-ray tubes operated at three different voltages. It was found that the continuous spectrum could be represented by a simple function containing only two constants. One of the constants proved to be independent of tube target material and applied voltage; the other, a function of voltage only. The integrated intensity of the continuous radiation was found to vary directly as the atomic number of the tube target and the square of the voltage applied.