X-ray Photoelectron Spectroscopy


Equipment in a lab
(Andrew Thron/UC Davis)

The Kratos Analytical Axis Supra is a x-ray photoelectron spectrometer (XPS) which provides the chemical composition and electronic structure of the near-surface region of the sample (within the top 10 nm). The Axis Supra is equipped with a monochromated x-ray gun (Al and Ag anodes), an achromatic x-ray gun (Al and Mg anodes), and an ultraviolet photoelectron spectroscopy (UPS) He lamp. A hemispherical and spherical mirror analyzer equipped with a 128-channel delay-line detector allows for fast parallel imaging and excellent signal-to-noise ratio. The Axis Supra is also equipped with a Minibeam 4, Ar+ ion gun designed for surface cleaning and relative depth profiling.  Furthermore, the heating and cooling holders allow the user to control temperature in the sample analysis chamber.  

An ultrahigh vacuum Surface Science Station (SSS) is attached to the analysis chamber by a load lock and gives the user in-situ capability of exposing samples to a variety of gas environments pre- and post-analysis without having to break vacuum. The Axis Supra is also equipped with a high tilt sample arm which can be used to acquire angle-resolved XPS (ARXPS). 

The acquisition of the Kratos Analytical Axis Supra XPS was funded by a National Science Foundation Major Research Instrumentation grant, MRI- 1828238 (PI: Kristi Koski, Co-PIs Charles S Fadley, Coleman Kronawitter, Frank Osterloh, and Jesus Velazquez). 


Monochromatic Source
  • Al anode Kα : 1486.6eV
  • Ag anode Lα : 2984.2eV
Achromatic Source
  • Al anode Kα: 1486.6eV
  • Mg anode Kα: 1254 eV
UPS Lamp
  • He (I): 21.22eV
  • He (II): 40.80eV


Heat and Cool Stage
  • < -100°C to 800°C.
Surface Science Station
  • Dose up to three gases simultaneously.
  • Spatial resolution of 1µm.
  • Ar+ ions from 500eV to 4keV.


108 Kemper Hall.

View Recharge Rates

XPS Resources

Simulation Packages

NIST’s Simulation of Electron Spectra for Surface Analysis (SESSA) is a great tool for simulating your AES XPS Spectra. Samples can be configured in multiple ways: Multilayers, Islands, wires, spheres on substrates. You can specify the composition of your material, specify peak positions based on reference data from similar compounds, and the operating parameters of the spectrometer. The simulated data can then be compared against the acquired data.

The SESSA package can be downloaded for free on the NIST website. It is available for Windows, Mac, and Linux operating systems.


Kratos, the manufacturer of our Axis Supra.

http://www.xpsfitting.com/ is an excellent resource for analyzing XPS and Auger data. The website covers general analysis methods as well as element specific discussions on peak shapes and positions.

NIST’s X-ray Photoelectron Spectroscopy Database has an extensive database of binding energies for elements in specific compounds. This is an excellent reference to determine constraints on peak positions when fitting XPS spectra.


ESCape is the software written By Kratos to acquire and analyze XPS data from the Supra. An offline version of ESCape is avalible to all the Supra users in AMCaT upon request.

CasaXPS is a popular software package for fitting and analyzing XPS data.


XPS Guides for Data Acquisition and Analysis  [1–8]

[1]      D. R. Baer, K. Artyushkova, H. Cohen, C. D. Easton, M. Engelhard, T. R. Gengenbach, G. Greczynski, P. Mack, D. J. Morgan, and A. Roberts, XPS Guide: Charge Neutralization and Binding Energy Referencing for Insulating Samples, J. Vac. Sci. Technol. A 38, 31204 (2020).

[2]      D. R. Baer, K. Artyushkova, C. Richard Brundle, J. E. Castle, M. H. Engelhard, K. J. Gaskell, J. T. Grant, R. T. Haasch, M. R. Linford, C. J. Powell, A. G. Shard, P. M. A. Sherwood, and V. S. Smentkowski, Practical Guides for X-Ray Photoelectron Spectroscopy: First Steps in Planning, Conducting, and Reporting XPS Measurements, J. Vac. Sci. Technol. A 37, 31401 (2019).

[3]      P. R. Davies and D. J. Morgan, Practical Guide for X-Ray Photoelectron Spectroscopy: Applications to the Study of Catalysts, J. Vac. Sci. Technol. A 38, 33204 (2020).

[4]      C. D. Easton, C. Kinnear, S. L. McArthur, and T. R. Gengenbach, Practical Guides for X-Ray Photoelectron Spectroscopy: Analysis of           Polymers, J. Vac. Sci. Technol. A 38, 23207 (2020).

[5]      G. H. Major, N. Fairley, P. M. A. Sherwood, M. R. Linford, J. Terry, V. Fernandez, and K. Artyushkova, Practical Guide for Curve Fitting in X-Ray Photoelectron Spectroscopy, J. Vac. Sci. Technol. A 38, 61203 (2020).

[6]      C. J. Powell, Practical Guide for Inelastic Mean Free Paths, Effective Attenuation Lengths, Mean Escape Depths, and Information Depths in x-Ray Photoelectron Spectroscopy, J. Vac. Sci. Technol. A 38, 23209 (2020).

[7]      A. G. Shard, Practical Guides for X-Ray Photoelectron Spectroscopy: Quantitative XPS, J. Vac. Sci. Technol. A 38, 41201 (2020).

[8]      S. Tougaard, Practical Guide to the Use of Backgrounds in Quantitative XPS, J. Vac. Sci. Technol. A 39, 11201 (2020).

[9]      A. R. Head and S. Nemšák Strategies for the Collection, Analysis and Interpretation of APXPS Data, ACS Symposium Series, 1396, 297-313 (2021)