AbstractOur recently proposed theory on X-ray energy responses of semiconductor detectors is based on the physics principle of the three-dimensional diffusion of X-ray-produced charges in a semiconductor field-free substrate region. In this paper, this diffusion process is experimentally verified using a spatially distributed charge profile produced by an X-ray beam in a multi-channel semiconductor detector. Actual X-ray profile data are distorted because of the effect of the diffusion. Using this theoretical principle, a new X-ray analysis method for obtaining plasma electron temperature profiles (that have no dependence on plasma densities) is proposed.