Absolute cross section measurements of ²³⁸U(n,f) and ²³⁷Np(n,f) in the neutron energy range 1-2.4 MeV

¹ National Physical Laboratory, Hampton Road, Teddington, Middlesex, TW11 0LW, United Kingdom
² EC-JRC-Directorate G-Nuclear Safety & Security, Unit G.2, Retieseweg 111, 2440 Geel, Belgium

^* e-mail: paula.salvador.castineira@npl.co.uk

Published online: 5 June 2019

Abstract

New standard (n,f) cross sections other than ²³⁵U are important to study the relevant cross sections for Generation-IV power plants. A specific need for such standards is for performing new experiments with quasimonoenergetic neutron beams, such as those produced by Van de Graaf accelerators. Neutrons down-scattered to low energies in the experimental environment, so called room-return, become relevant for this type of measurements. Hence, a standard (n,f) cross section with a fission threshold is of great interest, in order to suppress the contribution from room-return background. For this reason we have performed two experiments at the VDG of the National Physical Laboratory to measure absolutely the (n,f) cross sections of ²³⁵U, ²³⁸U and ²³⁷Np in the fast neutron energy region. Our preliminary results are in agreement with the most up-to-date evaluations.