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XCOM: Photon Cross Sections Database

NIST Standard Reference Database 8 (XGAM)

M.J. Berger, J.H. Hubbell, S.M. Seltzer, J. Chang, J.S. Coursey, R. Sukumar, D.S. Zucker, and K. Olsen
NIST, PML, Radiation Physics Division

Last Update to Data Content: November 2010 | NBSIR 87-3597  |  Version History  |  Disclaimer | DOI:

© 1990, 1998 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved. NIST reserves the right to charge for these data in the future.

Note on NIST X-ray Attenuation Databases


A web database is provided which can be used to calculate photon cross sections for scattering, photoelectric absorption and pair production, as well as total attenuation coefficients, for any element, compound or mixture (Z ≤ 100), at energies from 1 keV to 100 GeV.



  1. Introduction
  2. Database for Elements
  3. Interpolation and Combination
  4. How to Run the XCOM Program
  5. References
  6. Database Search Form
  7. ASCII output for text-based browsers
  8. Download Your Own Copy of XCOM Version 3.1

This work was supported in part by the Department of Energy, Office of Health and Environmental Research, Washington, DC 20585; NIST's Standard Reference Data Program, and by NIST's Systems Integration for Manufacturing Applications (SIMA) Program.


NIST Standard Reference Database 8
Customer Support
Online: March 1998 - Last Update: November 2010



Created September 17, 2009, Updated November 26, 2019