Validation of Nuclear Data using Lawrence Livermore Pulsed Sphere Experiments

Starting from the late ‘60s, a series of pulsed sphere experiments have been performed at Lawrence Livermore National Laboratory (LLNL) where an almost isotropic 14 MeV neutron source (produced by a T(d,n)4He reaction) was placed at the center of a spherical target assembly. These pulsed sphere experiments are a lot more sensitive to cross section data and even angular distributions when compared to integral benchmarks. This aspect alone makes them prime candidates for validating nuclear data because even the smallest differences will be very clear. In this paper, we will discuss the results from simulating pulsed sphere experiments on materials such as liquid oxygen, magnesium, lead, bismuth, titanium, iron, concrete and 239Pu. Some of these examples (for instance the magnesium spheres) will illustrate the power of this type of experiments.