Gamma-Ray Albedo Calculations Using Moments Method

This paper shows the results of a gamma-ray backscattering calculation using the moments method. Results are shown for the differential angular energy distribution of gamma-ray flux backscattered from semi-infinite media of aluminum and iron. A plane normal source of 0.66-MeV gamma rays from ¹³⁷Cs is simulated in the calculation. A comparison is shown between the calculated albedo spectra and results from an experiment. The calculated albedo distributions were slightly higher in the multiple scattering peak area for angles greater than 130 deg; otherwise, the comparisons were very good. The slight discrepancies can be explained by the finite slab boundary effects from the experiment.