COMMISSIONING AND CHARACTERIZATION OF THE SAXS PILATUS 300K DETECTOR FOR BL4-2

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We characterized the performance of the new Pilatus 300K detector shortly after its installation on the beam line. Our experimental results assured that the detector works according to its factory specifications. Most notably, it exhibits virtually no noise and zero dark counts by the virtue of being a photon counting detector. An exceptionally high linearity over at last 6 orders of magnitude has been recorded in actual experiments. The pixel saturation level is 4 orders of magnitude higher than the strongest level of scattering signal we have so far recorded so that we anticipate nearly 10 orders of excellent dynamic range. We recorded the same virus solution scattering pattern using our Rayonix MX225HE detector for direct comparison with Pilatus 300K. It was found that the exceptionally narrow point spread function of Pilatus 300K allows very accurate recording of scattering signal from large macromolecular complexes and assemblies such as virus particles, which exhibit rapid decline in scattering signal near the beam stop and very sharp scattering minima. We also found that both detectors provide similarly high data quality with a comparably high overall signal-to-noise ratio after taking into account different pixel sizes and photon detection efficiencies. We have used our Pilatus 300K in several of actual time-resolved x-ray solution scattering studies before summer shutdown. We plan on incorporating this detector in our standard Blu-Ice data collection system in near future.