On the correction of reflection intensities recorded on imaging plates for incomplete absorption in the phosphor layer.

When an X-ray beam is incompletely absorbed in the phosphor layer of an imaging plate (IP), a correction for oblique incidence of the beam on the plate becomes imperative. The perpendicular transmission through the phosphor of Fuji imaging plates has been measured as 30% (HR-IIIN plate, conventional source) for 0.707 Å radiation, and 50 and 85% (BASIII plate, synchrotron radiation) for 0.642 and 0.394 Å radiation, respectively. For a given wavelength, the correction factor is a function of the angle between the diffracted beam and the normal to the surface of the plate. For a flat IP, mounted perpendicularly to the incident beam, the correction increases with the 2θ angle of the reflections, but for other orientations of the IP the dependence is more complex.