Calculation of modulation transfer functions of x-ray fluorescent screens.

Formulas have been derived for calculating the modulation transfer function of x-ray intensifying screens. Emphasis has been placed on simplified models where results can be obtained in closed form and a physical understanding more easily realized. For selected cases, the MTF's of transparent screens are calculated by direct integration. The MTF's of diffusing screens are determined from suitable approximate solutions of the Boltzmann equation. The intermediate case and the transition from scattering to nonscattering are discussed. As a byproduct, formulas for light output and signal-to-noise ratio are obtained.