Commissioning of the NeutronSTARS Array to Measure (n,xn) and (n,fxn) Reactions through the Surrogate Method.
Fission neutron multiplicities and (n,xn) data is imperative for nuclear models
that support critical safety, nuclear nonproliferation, and stockpile stewardship. The first
experimental measurement where a surrogate reaction was used to determine the neutron
multiplicity, and (n,2n) cross section for any isotope was performed for Pu-241 using the
newly commissioned NeutronSTARS (Neutron-Silicon Telescope Array for Reaction Studies)
array. Due to the short half-life (14.3 yrs) of Pu-241, inelastic scattering on Pu-242
(half-life =375,000 yrs) with 55 MeV alpha particles was used as a surrogate for Pu-241
(n,f). An overview of the NeutronSTARS array characteristics are presented. Additionally,
the fission neutron multiplicity, and the (n,2n) cross sections for equivalent neutron
energies up to 20 MeV are discussed and reported.