Megapixel high-dynamic-range low-energy x-ray imager for synchrotron applications

New synchrotron facilities such as the European Synchrotron Radiation Facility rely on the development of new detectors to take full advantage of the dramatic increase in the brilliance of their x-ray beamlines. A novel detector system based on modified x-ray image intensifiers (XRII) optically coupled to CCD cameras is described. Different options fit specific requirements, essentially trading resolution against speed. The energy range covers from 5 to 25 keV with the special beryllium windowed XRII, and up to 100 keV with standard medical imager tubes. Input size is 200 mm in diameter, with electronic zooming capability down to (phi) 100 mm. A 50% MTF is reached for 17 line pairs/cm. More important is the extremely narrow wings of the point spread function: full width at 0.1% of maximum is less than 1 mm. Noise is negligible in most applications, being equivalent to a few x-ray photons/s.cm2, so that single x-ray photons are easily distinguished. Commercially available slow scan CCD cameras allow 16 bit dynamic range megapixel images to be read-out in 10 - 20s. Faster designs studied at the ESRF using multi-output CCD already make it possible to acquire several images per second, and ultra fast systems with only 512 X 512 pixels are expected to reach up to 300 images/s while maintaining a dynamic range of 1000:1.