Item

Abstract

In this article we describe an x‐ray photoelectron spectrometer that can either be used as an ultra‐high vacuum instrument (p < 10−10 mbar) or, after insertion of a movable aperture, to analyse materials at ambient pressures up to 1 mbar. We will describe the basic design of the instrument, and the methods used to determine the pressure at the location of photoelectron ejection. One way to estimate the pressure is by attenuation of the substrate signal by the gas phase and comparing experimental with published ionization cross‐sections; the second method uses condensation isobars. Examples are given for gas‐phase spectra. Application of the instrument in surface science studies is demonstrated by two examples where surfaces were analysed under high‐pressure conditions as a function of temperature, showing that the instrument allows steady‐state equilibrium measurements of surface composition.