Design, simulation and construction of an electron-electron coincidence spectrometer

The design, simulation, and construction of an electron impact spectrometer for coincident detection of both outgoing electrons in an electron impact ionization, (e,2e) experiment, is described. The spectrometer is a relatively conventional electrostatic-based design which consists of an electron gun, two 180 degrees hemispherical analyzers, a Faraday cup, and an optional photon detector for possible triple coincidence experiments. An electron ray-tracing simulation program, SIMION, is used to predict characteristics of the gun and analyzer along with several multi-element electrostatic lenses. A full description of the spectrometer layout, its working principle and the expected behavior obtained by computer simulations are presented. (c) 2007 Elsevier B.V. All rights reserved.