An Auger photoelectron coincidence spectrometer

The feasibility of photoelectron Auger electron coincidence spectroscopy from solid surfaces has been demonstrated by Haak et al. [Ph. D. thesis, University of Groningen, The Netherlands, 1983; Phys. Rev. Lett. 41, 1825 (1978); Rev. Sci. Instrum. 55, 696 (1984)]. They were able to show the considerable power of the technique in deconvoluting the L₂₃M ₄₅M₄₅ line of Cu by finding those parts of the line that were due to a 2p_3/2 hole and those which were due to a 2p _1/2 hole. However, the technique is a difficult one, requiring two analyzers rather than one and complex coincidence electronics. Even then a single spectrum can take weeks to acquire. This initial work was followed up by Jensen et al. [Phys. Rev. Lett. 62, 71 (1989); Physical Electronics Conference abstract A-5, July, 1988] using a synchrotron to provide the radiation and a means of getting very good timing resolution. They were able to acquire Cu spectra in 2-3 days using this system. We have constructed a set of electron analyzers specifically for this experiment. We used the ideas of Völkel and Sandner [J. Phys. E 16, 456 (1983)] to produce analyzers that have good angular acceptance, good energy resolution, and very good timing resolution. With this system we are able to measure coincidence line shapes, for elements with large enough cross section, within a few days using a standard laboratory dc x-ray source.