The Distribution of Energy in the Continuous X-ray Spectrum

Abstract

Ionization Spectra WHEN a beam of X-rays is analyzed by a crystal, the result, familiar to us all nowadays, is a spectrum of a type more or less like those in Fig. 1. This figure, taken from a paper by Ulrey1 in 1918, shows the spectra of three elements, plotted in the usual way, with the abscissae representing wave lengths and the ordinates the measured intensities. One of the spectra shows characteristic lines, and all show the continuous spectrum, which begins at the short-wave limit given by the quantum law and continues indefinitely into the longer wave lengths. This continuous spectrum always contains a large part of the energy, if not practically all, and it is therefore a problem of great importance to find out how the energy is distributed among the different wave lengths. This problem is important for two reasons: first, in finding evidence on the mechanism within the atom, that emits these rays; and second, for the practical purpose of furnishing more exact data for the theory of radiotherapy. A...