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NIST Database for the Simulation of Electron Spectra for Surface Analysis (SESSA), Version 2.1.1



Cedric J. Powell


The purpose of the NIST Database for the Simulation of Electron Spectra for Surface Analysis (SESSA) is to facilitate quantitative interpretation of Auger-electron and X-ray photoelectron spectra (AES/XPS) for surface analysis and to improve the accuracy of quantification in routine analysis. For this purpose, the database contains physical data required to perform quantitative interpretation of an electron spectrum for a specimen with a given composition. Retrieval of relevant data is performed by a small expert system that queries the comprehensive databases. A simulation module is also available within SESSA that provides an estimate of peak intensities as well as the energy and angular distribution of the emitted electron flux. The information needed by the expert system to accomplish its task closely matches instrument settings made by an experimenter when actually performing a measurement and is complemented by an initial estimate of the sample composition. SESSA can be used for two main applications. First, data are provided for many parameters needed in quantitative AES and XPS (differential inverse inelastic mean free paths, total inelastic mean free paths, differential elastic- scattering cross sections, total elastic-scattering cross sections, transport cross sections, photoionization cross sections, photoionization asymmetry parameters, electron-impact ionization cross sections, photoelectron lineshapes, Auger-electron lineshapes, fluorescence yields, and Auger-electron backscattering factors). Second, Auger-electron and photoelectron spectra can be simulated for layered samples and for samples with selected nanomorphologies such as islands, spheres, and layered spheres. This version of SESSA contains a fix of a software bug in calculations of the photoelectron source angular distribution in the non- dipolar case.
Natl Std. Ref. Data Series (NIST NSRDS) - 100
Report Number


Auger electron spectroscopy, nanomorphologies, reference data, simulations, surface analysis, x-ray photoelectron spectroscopy


Powell, C. (2018), NIST Database for the Simulation of Electron Spectra for Surface Analysis (SESSA), Version 2.1.1, Natl Std. Ref. Data Series (NIST NSRDS), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed June 16, 2024)


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Created September 18, 2018, Updated January 27, 2020