DIFFERENTIAL NEUTRON ALBEDO FOR THIN SLABS.
Technical rept. Sep 64-Jan 66.
NAVAL CIVIL ENGINEERING LAB PORT HUENEME CALIF
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Data giving the experimental angular distribution of differential albedo for thermal neutrons incident upon thick scatters of lead, high density concrete, and iron have been collected. Differential albedo of thermal neutrons on aluminum, iron, and polyethylene as a function of the materials thickness for a given incident and exit angles is shown. These data are compared with a theoretical formula. Experimental verification of the theoretical formula is quite good for the angular variables. Asymptotic limits of the formula for thick and thin scatters are as would be expected physically. The exponential dependence of the formula upon thickness agrees roughly within experimental errors. Reasons for inaccuracies in the magnitude of differential albedo are discussed. An extension to general albedo measurements for thin scatterers at any energy is described. This method, employing elemental scatterers, is shown to yield reliable results in the thermal region when the thickness of the material is less than one mean free path. The method also does away with the need for a collimated detector in differential albedo measurements for thin scatterers. Author
- Nuclear Radiation Shielding, Protection and Safety