A modification of Kramers' law for the X-ray continuum from thick targets

The intensity of an x-ray continuum has been generated theoretically for incident electron energies between 10 and 45 keV, radiated photon energies between 2 and 40 keV and over the whole range of atomic numbers (from Z=1 to 100). For these cases a relatively simple expression was found which shows the dependence of continuous radiation on the atomic number, incident electron energy and radiated energy. In order to compare observed intensities with this expression, we have made corrections for self-absorption in the target, for loss of ionization due to backscatter and for absorption by the exit window of an x-ray tube. Our expression provides a better description of experimental observations than does Kramers' equation. (author)