HIGH-PERFORMANCE X-RAY-DETECTOR FOR APPEARANCE-POTENTIAL SPECTROSCOPY

A high-performance detector for soft x-ray appearance potential spectr oscopy is described. It basically consists of an alkali halide photon- to-electron converting layer evaporated onto a self-supporting amorpho us carbon foil. This combination absorbs the low energy photons thereb y increasing the signal-to-noise ratio. Further improvement of the sig nal-to-noise ratio is achieved by an additional x-ray filter. The choi ce of filter and converter material depends on the characteristic radi ation of interest. The electrons emitted from the converter are detect ed by means of a microchannel plate. With this detector a signal-to-no ise ratio of 150 was obtained at the diamond appearance potential spec troscopic peak for 5 mC charge per point. (C) 1998 American Vacuum Soc iety. [S0734-2101(98)02404-X].