Design and construction of a high-stability, low-noise power supply for use with high-resolution electron energy loss spectrometers

Abstract

The design and construction of a high-stability, low-noise power supply which provides potentials for the lens and analyzer elements of a 127° Ehrhardt-type high-resolution electron energy loss spectrometer (HREELS) is described. The supply incorporates a filament emission-control circuit and facilities for measuring electron beam current at each spectrometer element, thus facilitating optimal tuning of the spectrometer. Spectra obtained using this supply are shown to have a four-fold improvement in signal-to-noise ratio and a higher resolution of the vibrational loss features when compared with spectra taken using a previously existing supply based on passive potential divider networks.