Title:	Electron Energy Loss Spectrometers
Authors:	Ibach, Harald
Keywords:	Electron Energy Loss Spectrometers
Issue Date:	1991
Publisher:	Springer
Description:	After building electron energy loss spectrometers for many years, we felt the need to develop a scientific basis for their construction. Progress in this direction was impeded by the fact that the apparently most successful designs involved cylin- drical deflectors. Lens systems properly adapted to the one-dimensional focusing in cylindrical deflectors cannot possess rotational symmetry, so that standard pro- grams could not be used. Hence we began our expedition into the well-established field of electron optics with the development of programs for lens systems that exhibit merely C2„ symmetry rather than rotational symmetry. The tremendous success of lenses calculated with such programs encouraged us to investigate also the other electron optical elements in a spectrometer more closely. While it has been recognized since the early work of Kuyatt and Simpson that the maximum monochromatic current that an electron optical device can produce is limited by space charge, that is, by the repulsive forces between the electrons, the details of the effect of the space charge on electrostatic deflectors were not understood. This volume is the first to describe relatively straightforward, an- alytical, solvable models for the effect of the space charge on the fast-order focusing properties of cylindrical deflectors. The analytical considerations are then extended by numerical simulations of electrostatic deflectors under space charge conditions, and the design of the deflectors is optimised according to these considerations. Space-charge-saturated monochromators require feed beams with specified angular apertures. We have therefore devoted one chapter to the design of emission systems operating under space charge conditions at low energies.
URI:	http://10.6.20.12:80/handle/123456789/76411
ISBN:	3-540-52818-0
Appears in Collections:	Chemistry

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