Research and analysis

Gamma source shielding: use of the MCNP-4C2 simulation code

This report (HPA-RPD-030) describes the use of the MCNP-4C2 simulation code to determine the transmission of 0.511 and 0.662 MeV photons through concrete, lead and iron.

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The Monte Carlo simulation code MCNP-4C2 is employed to determine the transmission of 0.511 MeV gamma rays through concrete, lead or iron shields, with the transport calculations performed for a simple, cylindrically defined configuration.

The reliability of the transport method is assessed by performing the calculations for selected thicknesses of material (concrete, lead or iron) with a 0.662 MeV photon source, and comparing the results with measurement data available in the literature. In almost all cases, acceptable agreement is reported; the discrepancies existing in the remaining few are discussed. Justification for some of the assumptions and approximations inherent in this highly simplified geometry is also presented.