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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

© 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

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

Stephen Seltzer
Radiation Physics Division
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