ABSTRACT
We have built an x-ray spectrometer in a von Hamos configuration based on a highly annealed pyrolytic graphite crystal. The spectrometer is designed to measure x-ray emission in the range of 2-5 keV. A spectral resolution E/ΔE of 4000 was achieved by recording the elastic peak of photons issued from the GALAXIES beamline at the SOLEIL synchrotron radiation facility.
ABSTRACT
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.).
ABSTRACT
We describe a bent-crystal spectrometer adapted to measure x-ray emission resulting from core-level excitation of gas-phase molecules in the 0.8-8 keV energy range. The spectrometer is based on the Johann principle, and uses a microfocused photon beam to provide high-resolution (resolving power of approximately 7500). A gas cell was designed to hold a high-pressure (300 mbar) sample of gas while maintaining a high vacuum (10(-9) mbar) in the chamber. The cell was designed to optimize the counting rate (2000 cts/s at the maximum of the Cl Kalpha emission line), while minimizing self-absorption. Example of the Kalpha emission lines of CH(3)Cl molecules is presented to illustrate the capabilities of this new instrument.
