A theoretical comparison of electron energy analysers degraded so as to obtain high sensitivity

The signals and signal-to-noise ratios are calculated for Lorentzian and Gaussian inputs to unmodulated electron spectrometers with wide slits and to over-modulated spectrometers. Data which characterise the distortion of the output as compared to the input are given in graphical form. It is concluded that unmodulated spectrometers give a small but useful increase in signal-to-noise ratio for peaks on low backgrounds whilst introducing the least distortion of peak shape. (Auth.)