@article{AbboudSendPashniaketal.2013,
  author    = {Abboud, Ali and Send, Sebastian and Pashniak, N. and Leitenberger, Wolfram and Ihle, Sebastian and Huth, M. and Hartmann, Robert and Str{\"u}der, Lothar and Pietsch, Ullrich},
  title     = {Sub-pixel resolution of a pnCCD for X-ray white beam applications},
  series = {Journal of instrumentation},
  volume    = {8},
  journal   = {Journal of instrumentation},
  number    = {3},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {1748-0221},
  doi       = {10.1088/1748-0221/8/05/P05005},
  pages     = {17},
  year      = {2013},
  abstract  = {A new approach to achieve sub-pixel spatial resolution in a pnCCD detector with 75 x 75 mu m(2) pixel size is proposed for X-ray applications in single photon counting mode. The approach considers the energy dependence of the charge cloud created by a single photon and its split probabilities between neighboring pixels of the detector based on a rectangular model for the charge cloud density. For cases where the charge of this cloud becomes distributed over three or four pixels the center position of photon impact can be reconstructed with a precision better than 2 mu m. The predicted charge cloud sizes are tested at selected X-ray fluorescence lines emitting energies between 6.4 keV and 17.4 keV and forming charge clouds with size (rms) varying between 8 mu m and 10 mu m respectively. The 2 mu m enhanced spatial resolution of the pnCCD is verified by means of an x-ray transmission experiment throughout an optical grating.},
  language  = {en}
}
@article{LeitenbergerHartmannPietschetal.2008,
  author    = {Leitenberger, Wolfram and Hartmann, Robert and Pietsch, Ullrich and Andritschke, Robert and Starke, Ines and Str{\"u}der, Lothar},
  title     = {Application of a pnCCD in X-ray diffraction : a three-dimensional X-ray detector},
  doi       = {10.1107/S0909049508018931},
  year      = {2008},
  abstract  = {The first application of a pnCCD detector for X-ray scattering experiments using white synchrotron radiation at BESSY II is presented. A Cd arachidate multilayer was investigated in reflection geometry within the energy range 7 keV < E < 35 keV. At fixed angle of incidence the two-dimensional diffraction pattern containing several multilayer Bragg peaks and respective diffuse-resonant Bragg sheets were observed. Since every pixel of the detector is able to determine the energy of every incoming photon with a resolution Delta E/E similar or equal to 10(-2). a three-dimensional dataset is finally obtained. In order to achieve this energy resolution the detector was operated in the so-called single-photon- counting mode. A full dataset was evaluated taking into account all photons recorded within 10(5) detector frames at a readout rate of 200 Hz. By representing the data in reciprocal-space coordinates, it becomes obvious that this experiment with the pnCCD detector provides the same information as that obtained by combining a large number of monochromatic scattering experiments using conventional area detectors.},
  language  = {en}
}
@article{SendAbboudHartmannetal.2013,
  author    = {Send, Sebastian and Abboud, Ali and Hartmann, Robert and Huth, M. and Leitenberger, Wolfram and Pashniak, N. and Schmidt, J. and Str{\"u}der, Lothar and Pietsch, Ullrich},
  title     = {Characterization of a pnCCD for applications with synchrotron radiation},
  series = {Nuclear instruments \& methods in physics research : a journal on accelerators, instrumentation and techniques applied to research in nuclear and atomic physics, materials science and related fields in physics ; A, Accelerators, spectrometers, detectors and associated equipment},
  volume    = {711},
  journal   = {Nuclear instruments \& methods in physics research : a journal on accelerators, instrumentation and techniques applied to research in nuclear and atomic physics, materials science and related fields in physics ; A, Accelerators, spectrometers, detectors and associated equipment},
  number    = {5},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0168-9002},
  doi       = {10.1016/j.nima.2013.01.044},
  pages     = {132 -- 142},
  year      = {2013},
  abstract  = {In this work we study the response of a pnCCD by means of X-ray spectroscopy in the energy range between 6 key and 20 key and by Laue diffraction techniques. The analyses include measurements of characteristic detector parameters like energy resolution, count rate capability and effects of different gain settings. The limit of a single photon counting operation in white beam X-ray diffraction experiments is discussed with regard to the occurrence of pile-up events, for which the energy information about individual photons is lost. In case of monochromatic illumination the pnCCD can be used as a fast conventional CCD with a charge handling capacity (CHC) of about 300,000 electrons per pixel. If the CHC is exceeded, any surplus charge will spill to neighboring pixels perpendicular to the transfer direction due to electrostatic repulsion. The possibilities of increasing the number of storable electrons are investigated for different voltage settings by exposing a single pixel with X-rays generated by a microfocus X-ray source. The pixel binning mode is tested as an alternative approach that enables a pnCCD operation with significantly shorter readout times.},
  language  = {en}
}
@article{SendAbboudLeitenbergeretal.2012,
  author    = {Send, Sebastian and Abboud, Ali and Leitenberger, Wolfram and Weiss, Manfred S. and Hartmann, Robert and Str{\"u}der, Lothar and Pietsch, Ullrich},
  title     = {Analysis of polycrystallinity in hen egg-white lysozyme using a pnCCD},
  series = {Journal of applied crystallography},
  volume    = {45},
  journal   = {Journal of applied crystallography},
  number    = {6},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {0021-8898},
  doi       = {10.1107/S0021889812015038},
  pages     = {517 -- 522},
  year      = {2012},
  abstract  = {A crystal of hen egg-white lysozyme was analyzed by means of energy-dispersive X-ray Laue diffraction with white synchrotron radiation at 2.7 angstrom resolution using a pnCCD detector. From Laue spots measured in a single exposure of the arbitrarily oriented crystal, the lattice constants of the tetragonal unit cell could be extracted with an accuracy of about 2.5\%. Scanning across the sample surface, Laue images with split reflections were recorded at various positions. The corresponding diffraction patterns were generated by two crystalline domains with a tilt of about 1 degrees relative to each other. The obtained results demonstrate the potential of the pnCCD for fast X-ray screening of crystals of macromolecules or proteins prior to conventional X-ray structure analysis. The described experiment can be automatized to quantitatively characterize imperfect single crystals or polycrystals.},
  language  = {en}
}
@article{SendvonKozierowskiPanzneretal.2009,
  author    = {Send, Sebastian and von Kozierowski, Marc and Panzner, Tobias and Gorfman, Semen and Nurdan, Kivanc and Walenta, Albert H. and Pietsch, Ullrich and Leitenberger, Wolfram and Hartmann, Robert and Str{\"u}der, Lothar},
  title     = {Energy-dispersive Laue diffraction by means of a frame-store pnCCD},
  issn      = {0021-8898},
  doi       = {10.1107/S0021889809039867},
  year      = {2009},
  language  = {en}
}