Quantitative XPS. Part I: Experimental determination of the relative analyser transmission function of two different spectrometers — a critical assessment of various methods, parameters involved and errors introduced

The relative analyser transmission functions of two different XPS spectrometers (VG ESCA‐3 Mk II and SSI X‐Probe of Fisons) have been determined experimentally by several methods presented in the literature. The transmission function of the VG ESCA‐3 Mk II can be expressed as T ∝ E a ( E a / E k ) n , where n is close to 0.8. The transmission function T of the SSI X‐Probe cannot be presented as a separate function of E a and E k and it is expressed as The possible influence of the efficiency D of the detector on the determined transmission functions is discussed. The advantages and disadvantages of the methods used are pointed out, together with their limitations and potential applications. The results show that some methods can only be applied to spectrometers such as the VG ESCA‐3 Mk II in which n is a constant or depends only on E k . The method proposed by Hemminger et al. [ Surf. Interface Anal. 15, 323 (1990)] has been shown to be applicable to both spectrometers but a systematic error can be introduced when D is not constant. Such a systematic error can be reduced by another method but this method can only be applied to spectrometers in which the transmission function is known for a given analyser energy.