The CoESCA station at BESSY: Auger electron–photoelectron coincidences from surfaces demonstrated for Ag MNN

In this work, we present the CoESCA station for electron-electron coincidence spectroscopy from surfaces, built in a close collaboration between Uppsala University and Helmholtz-Zentrum Berlin at BESSY II synchrotron facility Berlin, Germany. We start with detailed overview of previous work field coincidences, before describe setup its design parameters. The system is capable recording shot-to-shot resolved 6D datasets, i.e. kinetic energy two take off angles both coincident electrons. mathematics behind extracting analysing these multi-dimensional datasets introduced, focus on statistics, resulting fundamental limits signal-to-noise ratio implications acquisition times size raw data stream. functionality demonstrated example Auger electron - photoelectron coincidences silver surfaces photoelectrons Ag 3d core levels their corresponding MNN spectra originating different levels, 3d$_{3/2}$ 3d$_{5/2}$ could be separated further, two-hole state distributions were determined decay channels.