Electron pair emission from surfaces: Some general experimental considerations

We discuss some experimental facets of electron pair emission from surfaces using two different approaches. In the first case instrument consists a hemispherical analyzers which are operated with continuous primary beams electrons or photons. The second employs time-of-flight spectrometers require pulsed excitation source. A key quantity is ratio ‘true’ to ‘random’ coincidences can be determined in ways. Regardless type flux has adopt much smaller value than single spectroscopy. describe approaches obtain relevant count rates, particular concept operating delayed coincidence circuit. also address question on how compare types spectrometer terms their performance.