title: Application of an ePix100 detector for coherent scattering using a hard X-ray free-electron laser.
abstract: A prototype ePix100 detector was used in small-angle scattering geometry to capture speckle patterns from a static sample using the Linac Coherent Light Source (LCLS) hard X-ray free-electron laser at 8.34 keV. The average number of detected photons per pixel per pulse was varied over three orders of magnitude from about 23 down to 0.01 to test the detector performance. At high average photon count rates, the speckle contrast was evaluated by analyzing the probability distribution of the pixel counts at a constant scattering vector for single frames. For very low average photon counts of less than 0.2 per pixel, the `droplet algorithm' was first applied to the patterns for correcting the effect of charge sharing, and then the pixel count statistics of multiple frames were analyzed collectively to extract the speckle contrast. Results obtained using both methods agree within the uncertainty intervals, providing strong experimental evidence for the validity of the statistical analysis. More importantly it confirms the suitability of the ePix100 detector for X-ray coherent scattering experiments, especially at very low count rates with performances surpassing those of previously available LCLS detectors.
authors: Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
authors: Marcin
authors: M
authors: Sikorski
authors: Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
authors: Yiping
authors: Y
authors: Feng
authors: Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
authors: Sanghoon
authors: S
authors: Song
authors: Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
authors: Diling
authors: D
authors: Zhu
authors: Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
authors: Gabriella
authors: G
authors: Carini
authors: Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
authors: Sven
authors: S
authors: Herrmann
authors: Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
authors: Kurtis
authors: K
authors: Nishimura
authors: Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
authors: Philip
authors: P
authors: Hart
authors: Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
authors: Aymeric
authors: A
authors: Robert
keywords: X-rays; coherent scattering; detector; droplet algorithm; free-electron laser (FEL)