Study of the reactivity of silica supported tantalum catalysts with oxygen followed by in situ HEROS

Time and position sensitive photon detector for coincidence measurements in the keV energy range

The detection efficiency η of any particle detector is important, concerning acquisition time, but becomes even more critical when two particles are detected in coincidence, with a total efficiency η₁η₂, in order to allow a deeper understanding of complex processes induced by light or particle interaction with matter. Efficiency and resolution of a time and position sensitive x-ray detector are reported here. This system consists of a multilayer transmission photocathode and two micro-channel plates (MCPs) equipped with a delay line anode (DLA). The efficiency is found to be about 20% for Al Kα photons, while the spatial resolution is comparable to that of a standard DLA detector (about 100 μm). The fast response time of the detector combined with its efficiency should allow coincidence experiments between x-ray photons and other particles (electron, ions, etc.).