Angle and energy dispersive multichannel electron energy spectrometer for surface analysis

An angle and energy dispersive multichannel electron energy spectrometer, which is based on a toroidal energy analyzer (TEA) [R.W. van Boeyen, J.F. Williams, Rev. Sci. Instrum. 76 (2005) 063303], has been developed for the purpose of element identification on solid surfaces. This spectrometer can detect electrons outgoing in the plane perpendicular to the incident electron beam in a wide azimuth angle range of 245°. The performance of the spectrometer has been optimized by the elastic and the Auger electrons of argon gas with a thermal electron gun. Its ability to measure solid surface was demonstrated by the energy loss and Auger electron of amorphous carbon film. At the end, we implemented a scanning tunneling tip as the field-emission electron source, and obtained the energy loss spectrum of highly ordered pyrolytic graphite. The new setup has improved the detection efficiency by 2 orders of magnitude compared with traditional electrostatic analyzer, indicating its potential ability to realize two-dimensional scanning electron energy spectra of solid surface with near-field STM tip.