A prototype 8 × 8 pixel array X-ray detector for protein crystallography

An 8 × 8 pixel array X-ray detector prototype (< 15 keV) has been built and tested. This room temperature detector will significantly enhance time resolved Laue Protein Crystallography by two or three orders of magnitude compared to the present crystallographic phosphor imaging plates and CCD-type detectors. In addition, the detector will greatly accelerate the monochromatic crystallography data collection at synchrotron light sources where very intense X-ray fluxes above 5 × 108 photons/cm2/s are obtained. The detectors event-driven read out is based on the column architecture which can provide energy discrimination and sparse and frameless output displaying minimal dead time. For the targeted detector size of (1000 × 1000) pixels, average hit rates greater than 8 × 107 photons/s for the entire area appears achievable. To characterize the analog portion of the read out and the digital characteristics of the detector, the pixel electronics contains only the analog portion of the circuit and is independent of the surrounding cells. The conversion of a photon hit into a pixel address is generated by conventional external electronics. The measured results are very encouraging. The analog electronics demonstrate the capability of processing charge pulses at a rate of 1 × 106 photons/s/pixel, with an energy resolution of 480 eV (FWHM at 5.9 keV) at room temperature. The detector displays uniform digital behavior and has a very low point-spread function. The full-width at 1100 maximum is less than 1 pixel width (150 μm), which is less than (12) that of a CCD and (17) that of an imaging plate detector [1].