A new generation of Crystallographic detector for Multi-user Barkla X-ray laboratory

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X-ray crystallography offers the opportunity to observe highest level of details in protein and RNA/DNA molecules. It has delivered unrivalled knowledge of many biological processes including respiration, photosynthesis, cell signalling, receptor's activation and enzymatic mechanisms. The way we think of biology and biological processes has transformed due to our ability to determine high-resolution structures of even the most complex systems. It also has revolutionized modern drug discovery and structure-based drug/lead-compounds have become a commonplace. The tremendous success of X-ray crystallography over the last 30 years has largely been due to the availability of highly intense Synchrotron Radiation (SR) facilities. During the last couple of decades, the SR sources have seen tremendous progress in the performance in terms of brightness where the brightness gain has been twice as fast as the rate of improvement in semiconductors (Moore's law), The increasing X-ray photon density delivered by the increasingly brighter sources has required rapid development in beamlines, optical elements and detectors. A major improvement in detectors from photographic plates to image plate to Charged Coupled Detectors (CCDs) emerged at the end of last century. DIAMOND Synchrotron opened its operation with MX beamlines using large CCDs but all of these have been replaced by photon counting hybrid pixel array silicon detectors (HPC) - in fact DIAMOND set the pace of change capitalizing on the development of HPC detectors that originated at the Swiss Light Source. The laboratory sources have continued three important roles, namely (i) pre-screening of crystals, their initial characterisation and establishment of soaking conditions of ligands/compounds/inhibitors, (ii) determination of structures of well diffracting systems (in fact the number of structures determined using laboratory sources per annum currently is the same as in the 1980s/90s) and (iii) train and equip PhD students and PDRA with in-depth skills not just in the use (as a user) but acquire in-depth understanding of instrumentation as well as the subtleties of data collection. The laboratory sources (and associated optics) have also improved and detector technology is also advancing but a decade or so behind the synchrotron. Only recently the technology of photon counting hybrid pixel array silicon detectors has become available for laboratory sources at a fraction of the price compared to detectors that are being bought for synchrotrons. This reduction in price has been achieved by matching the specifications of these new generations of HPC detectors to the laboratory sources. X-ray detectors must collect, quantize and digitize incoming X-rays while preserving highly precise location information. State-of-the-art new generation HPC X-ray detectors can collect X-rays with exceptional (>99 %) quantum efficiency. In recent years reduction of pixel size has increased the quality of the data collected; similar to increasing screen resolution in high definition televisions. Dectris have led the way in hybrid pixel array detectors and their new EIGER range combine small pixel size with high quantum efficiency and signal to noise. The EIGER R range is tailored for more intense laboratory sources and is capable of high-count rates with continuous readout and have small (75 microns) pixels, similar to our current MAR225CCD, which is now 12 years old. The provision of this latest generation of detector will not only ensure continued successful operation of the Barkla laboratory but also will enhance our capabilities for weekly diffracting systems including membrane protein crystals and multi-component complexes.