Bildgebende Röntgendetektion mit Gasverstärkung durch Mikrostrukturen für Hochgeschwindigkeitsmessungen

Many biological and technical applications at synchrotron radiation facilities require fast X-ray imaging detectors with good temporal and spatial resolution and large sensitive area. Motivated by the absence of commercially available detectors for these purposes, this thesis describes detailed studies of a novel gaseous single photon counter with gas amplification by micro pattern devices. In this respect, the suitability of MicroCAT and GEM micro structures, their combination and constellations of double- and triple-GEM stages is investigated for utilisation in high speed measurements, which usually demand high photon fluxes. Since the high rate capability of the detector is mainly limited by space charge effects and by dead time, the studies are focussed on the optimisation of the charge transfer behaviour and the signal lengths but also on the gas gain performance in different gas mixtures and pressures. The truly two-dimensional determination of the event position is realised by an interpolating readout concept based on resistive charge division, providing a large sensitive area with only a few electronic channels at the same time. To fully exploit the asynchronous and parallel readout capability, a newly developed electronic preprocessing and readout system has specially been adapted to the interpolating readout concept, offering low dead times and a high readout speed owing to the use of a locally confined readout of the spatial and energy information. The optimisation of the detector system, presented here, with respect to high speed measurements successfully leads to a flexible tool providing a time resolution of the order of 100 ns and a rate capability > 10 6 photons s −1 in diffraction peaks. The total rate capability amounts to more than 2 · 10 5 photons cm −2 s −1 and is proportional to the sensitive area of the detector.