A study of 14 MeV neutrons buildup factor in paraffin wax, graphite and lead.

Abstract

The 14 MeV neutrons buildup factor in paraffin wax, graphite and lead have been experimentally determined using the BF3 counter up to a thickness of 2.5 mean free path ( mfp ).The dependence of the secondary neutrons spectrum transmitted from all selected materials on the thickness at the fixed incident neutron energy has also been studied using a liquid organic scintillation detector type NE 213. Results indicate that, the value of buildup factor remains close to unity up to penetration depths of 0.4 mfp and then increases when sample thickness increased. The neutron spectra obtained in this research depends on the material type and thickness. In general, the neutron spectra decrease with increasing sample thickness. Comparison of the experimental results obtained with the previously calculated neutron buildup factor shows a good agreement.