The spatial resolution of the screens in terms of the modulation transfer function (MTF(f))
as a function of the spatial frequency, was measured using a GenDex Xray generator available at RMD.
The MTF(f) calculation involved measuring the line spread function (LSF) of the screen from the image of an angled,
10 lm wide tantalum slit.
Fast Fourier transform of the LSF was obtained to produce theMTF(f) function [21]. Fig. 5 shows theMTF(f)
of the screens. The microstructured nature of the CsI(Tl) allows the screens to maintain high spatial resolution.