Characterization of a pnCCD for applications with synchrotron radiation

In this work we study the response of a pnCCD by means of X-ray spectroscopy in the energy range between 6 keV and 20 keV 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.

► The pnCCD acts as a four-dimensional detector for white X-rays. ► Its performance for applications with synchrotron radiation is investigated. ► The pnCCD can be used for single photon counting and photon integration. ► The operation mode depends on the local frequencies of pile-up events. ► The pnCCD can be optimized for X-ray spectroscopy and X-ray imaging.