A New Approximation for the Neutron Albedo

Empirical parameters for a new fast-neutron differential dose albedo formula are presented for water, concrete, iron, and lead and for ten energy bands between 0.1 and 10.0 MeV. Data are also presented for ²⁵²Cf spontaneous fission neutrons, 14-MeV neutrons, and thermal neutrons. The 24-parameter approximation, based on modern dose units, agrees with MCNP-calculated values within 10%. Revised data are also presented for a five-parameter secondary-photon albedo formula, proposed earlier by Maerker and Muckenthaler, that is within 20% of MCNP values for the four materials. Finally, these revised albedo formulas are applied to the problem of thermal neutrons transmitted through a three-legged duct and compared to previous experimental results.