Calculation of absolute intensities from X-ray imaging plates

A numerical technique for deriving a conversion factor between the output p ixel values from a scanned imaging plate and the actual incident X-ray phot on flux is proposed. The technique requires no external calibration by inde pendent detectors, but uses the statistical information inherent in the ima ge. As a test case, this technique was applied to a Fuji BAS2000 imaging-pl ate scanner. The calculation showed that, at 1.2 Angstrom, 163 (8) photons pixel(-1) were required to give one output unit of pixel intensity on an im age scanned 20 min after exposure. This conversion factor compared favourab ly with the independently measured conversion factor of 171.1 (5) photons p ixel(-1) (output unit)(-1) obtained from a high-quantum-efficiency Ge detec tor.