Construction of an ELS-LEED: an electron energy-loss spectrometer with electrostatic two-dimensional angular scanning

A new version of an energy-loss spectrometer with low-energy electron diffraction (ELS-LEED, Henzler type EELS) has been constructed. Different from the prototype spectrometer, which is equipped with a single-pass 127 degrees cylindrical deflector analyser, the present spectrometer consists of an Ibach-type double-pass monochromator, an enlarged single-pass analyser and some magnetic lenses in acceleration and deceleration lenses and in the electrostatic deflection unit for high-resolution LEED. As a preliminary result, with the Si(111)-7 x 7 surface, the present spectrometer showed an energy width (full with at half-maximum) of 18 meV at the quasi-elastic peak and a transfer width of 960 Angstrom at the (00) diffraction spot. Copyright (C) 2000 John Wiley & Sons, Ltd.