Experimental benchmark of the fast neutron spectroscopy using neutrons from DT reaction and evaluation of the shielding calculation methods

The objective of the present work has been the development of a experimental benchmark for the assessment of neutron shielding calculation methods, involving cross section data, cross section processing codes and transport codes. The experiment aimed at the determination of spatially dependent fast neutron energy spectrum emerging from a laminated shield of stainless steel polyethylene and lead. Van de Graaff accelerator 3H (d,n)4 He reaction provided neutrons for the experiments. The neutron energy spectrum was measured at different positions for several combinations of shielding materials. The liquid scintillator NE-213 measuring system was used for the data acquisition. The proton-recoil spectrum was unfolded through the FANTI code in the range of 2.5 to 17 MeV. Two methods for shielding calculation commonly used at the Reactor Physics Division of IPEN/CNEN-SP were evaluated. (author)