Detector Linearity and Deadtime Correction for Modern Photoelectron Spectrometers—Surface Analysis Insight Note

ABSTRACT Accurate quantitative analysis of X‐ray photoelectron spectroscopy (XPS) data relies on a linear relationship between the photoelectron intensities (in counts or count rate) reported from the spectrometer's detection system and the number or arrival rate of electrons at the detector. Deviations from linearity typically arise when electrons arrive at the detector in quick succession so that not all of them can be counted. The output from an electron detector usually requires an adjustment known as the deadtime correction , to ensure that the true count rate is reported. XPS users must be cognisant of the linearity range, wherein the detector's measured intensities are proportional to the true intensities. In this insight note, we outline the use of a modified version of the spectrum ratio method in ISO 21270 to determine the deadtime and linearity intensity range of a photoelectron spectrometer, including the maximum permissible count rate for acquiring photoelectron spectra. We have listed a series of recommendations for surface analysts to consider when determining their spectrometer's detector characteristics and provide explanations of paralytic (paralyzable) vs. nonparalytic (nonparalyzable) detectors, deadtime correction in single‐channel vs multichannel detectors, a method based on the spectrum ratio method and the effects of nonlinearity on XPS quantification.