Flux monitoring hard X-ray optics in a single electrode configuration
  To explore possibilities for X-ray flux monitoring on optical elements electrical responses of silicon and diamond single crystals and that of an X-ray mirror were studied under exposure to hard X-rays in a single electrode configuration in ambient air. To introduce flux monitoring as a non-invasive capability a platinum electrode was deposited on a small unexposed portion of the entrance surface of the crystals while for the X-ray mirror the entire mirror surface served as an electrode. It was found that the electrical responses are affected by photoemission and photoionization of the surrounding air. The influence of these factors was quantified using estimations of total electron yield and the ionization current. It is shown that both phenomena can be used for the non-invasive monitoring of hard X-ray flux on the optical elements. Relevant limits of applicability such as detection sensitivity and charge collection efficiency are identified and discussed. 
Stanislav Stoupin, Bing Shi, John Katsoudas
physics.ins-det