The estimation of X-ray spectral distributions from attenuation data by means of iterative computation

Abstract

An iterative computational method is described for estimating the spectral distributions of X-rays from attenuation data measured with various filtrations. A compact algorithm is derived from the use of a gradient scheme for minimization of a least-squares criterion function, and its theoretical convergence is also established. The feasibility of the method is studied in detail in a computer simulation using a hypothetical spectrum based on the Kramers theory. The application results to experimental data are illustrated about the spectral distribution from a 140 kV constant voltage X-ray source.