Experiments of Neutron Multiplication in Beryllium

Abstract

Using the Total Absorption Method, the neutron multiplications in beryllium have been measured. A deionized water sphere with outer radius of 75 cm and a polyethylene sphere with outer radius of 69 cm were used as the total neutron absorbers. Neutron distributions in the spheres were measured using ²³⁵U fission chambers. The relative and the efficiency-determined methods were compared. Important sources of experimental errors were detailly analyzed. 4 groups of neutron multiplications in beryllium up to 14.85 cm thick for two total absorbers and two methods of measurement have been obtained and agreement among them is satisfactory. Measured results have been compared with ANISN calculations using data from ENDF/B-IV. It is shown that the differences between calculations and experiments are up to 15%.