6Li(n,t)α reaction event-identification for the 235U(n,f)/6Li(n,t) cross section ratio measurement in the NIFFTE fissionTPC

Abstract

While nuclear data play an important role in nuclear physics applications, it has become important to have a better understanding of the data and try to minimize the uncertainties. In particular, there is a need for precision neutron-induced fission cross section measurements on fissile nuclei. Neutron-induced fission cross sections are typically measured as ratios, with a well-known standard in the denominator. While the 235U(n,f) reaction is a well measured standard, some light particle reactions are also well-known and their use as reference can provide information to remove shared systematic uncertainties that are present in an actinide-only ratio. A recent measurement of the 235U(n,f) reaction using as a reference the standard 6Li(n,t) reaction, was conducted at the Los Alamos Neutron Science Center using the NIFFTE collaboration’s fission time projection chamber (fissionTPC). The fissionTPC is a 2×2π charged particle tracker designed for measuring neutron-induced fission. Detailed 3D track reconstruction of the reaction products enables evaluation of systematic effects and corresponding uncertainties which are less directly accessible by other measurement techniques. This work focuses on the analysis for the event identification of the 6Li(n,t)α reaction in the fissionTPC.