DESIGN OF ELECTRON SPECTROMETERS

The aim of this work is to propose a state-of-the-art presentation of all that is needed for the realization and use of a modern electron spectrometer. The discussion includes practical guidelines accessible to non-specialists who wish to design their own instrument. The basic characteristics and the design principles of such devices are discussed, with emphasis on the key component: the energy analyser. The main types of electrostatic analysers are reviewed. Formulae, tables and graphs are presented for the determination of their main features, in particular their energy resolution. The data for the energy resolution are obtained from a general approach, for first- and second-order focusing analysers of any size or geometry and whose optical coefficients are known. A figure of merit is proposed for their comparison and various optimization criteria are discussed. Different electron-optical aspects dealing with the calibration of analysers, the modes of operation for various types of measurements, and fringing field shielding are also surveyed. An effort is made to recall the fundamental laws and concepts of electron optics. A presentation is given of the basic data needed for the choice and the design of a lens system suitable for the efficient transport of the electrons. The case of electron monochromators is the object of a specific discussion. The last part is a survey of the latest developments in the techniques of electron spectroscopy. The section deals principally with multichannel detection techniques and the novel types of analysers designed for that purpose.