Light angular distribution and modulation transfer function of a fluorescent screen excited by an electron beam

The angular distribution of the light emitted from a ZnCdS(Ag) phosphor screen excited by an electron beam is measured for different thicknesses of the screen and for two grain sizes. This angular distribution is found to have a divergence from the Lambert law. A theoretical model is proposed leading to an equation fitting to the experimental results. Using this equation the modulation transfer function (MTF) of the screen was calculated.