This document specifies a procedure by which the intensity scale of an X-ray photoelectron spectrometer which employs a concentric hemispherical analyser can be calibrated using low-density poly(ethylene). This document is applicable to instruments using quartz-crystal-monochromated Al Kα X-rays and is suitable for all instrument geometries. The intensity calibration is only valid for the specific settings of the instrument (pass energy or retardation ratio, lens mode, slit and aperture settings) used during the calibration procedure. The intensity calibration is suitable for intensity calibration at kinetic energies higher than 180 eV. This document is not applicable to XPS instruments which do not have a low energy electron flood source or instruments that have a non-linear intensity response. This document is not applicable to instruments and operating modes which generate significant intensity from electrons scattered internally in the spectrometer.