Biological X-ray diffraction measurements with a novel two-dimensional gaseous pixel detector

Abstract

In order to exploit the potential of modern X-ray diffraction studies to its full extent, a new generation of appropriate detectors is required. Here, a small prototype (28 × 28 mm2 active area) of a novel two-dimensional pixel detector is presented which satisfies most of the requirements. It is based on a gaseous single-photon counter with asynchronous readout and interpolating position encoding, combining the advantages of a pure pixel readout (high local and global rate capability) with those of a projecting readout (small number of channels). In order to demonstrate the suitability of this detector for X-ray diffraction applications, measurements at a synchrotron radiation source have been performed recording diffraction patterns from different biological samples (rat tail tendon collagen, phospholipid and protein crystal). These measurements have proven the good spatial resolution, the high intensity precision and the high local rate capability. Moreover, the single-photon readout was utilized in order to perform time-resolved measurements in the case of SAXS studies and to apply fine angular slicing in the case of protein crystallography. The detector has a high reliability and robustness, particularly when compared with conventional gaseous detectors, and the technology used can be easily extended to large active areas.