QUANTITATIVE AES - REDUCING ERRORS IN MEASURED ANALOG SPECTRAL INTENSITIES THROUGH CONTROL OF THE ELECTRON DETECTOR

AES spectra, when measured in the constant ΔE/E mode, may be distorted by the varying efficiency of the electron detector, usually a channel electron multiplier (CEM). In the analogue mode, this is a problem that increases as the emitted electron energy falls below 200 eV. Instruments may be modified by adding transparent meshes and by biasing the front of the CEM by 200 eV. In this way, the spectral distortion may be reduced by a factor of 10 at 50 eV, so that the resultant spectral shape is within ±10% of the true shape over the energy range 25–2000 eV. This small distortion may be calibrated accurately so that true spectra may be derived from all modified instruments with greater reliability and confidence than in unmodified instruments. Copyright © 1990 John Wiley & Sons Ltd.