The Berkeley Atlas: A database of absolute cross sections for inelastic, gamma-ray production with 14 MeV neutrons*

The accuracy of elemental composition measurements via active neutron interrogation is largely determined by the uncertainties in gamma production cross sections. In particular, there are several discrepancies and gaps in cross section libraries for gamma production through inelastic scattering (n,n’g). Therefore, we developed a technique for precise measurements of (n,n’g) at 14 MeV incident neutron energy. This technique is based on the Associated Particle Imaging (API) method, which allows the tagging of individual neutrons in correlation with alpha particles emitted by a Deuterium-Tritium (DT) source. This correlation provides several advantages including precise measurements (< 1% uncertainty) of the neutron flux on target -  which is a main driver of uncertainty in current techniques, no parasitic reactions from low-energy neutrons, and a large signal-to-noise ratio due to the background suppression capabilities of the system.

We will present the results for various targets, discuss progress to date, and future work on the "Berkeley Atlas", which is the production of a (n,n'g) database at 14 MeV incident neutron energy for several targets relevant to different applications.