Low-energy Proton Tracking with geant4 for the BL3 Experiment

The value of the neutron lifetime is very important, as it provides inputs in the quark mixing matrix constants in the Standard Model and in the primordial abundance of Helium-4 in Big Bang Nucleosynthesis. The goal of the BL3 experiment is to investigate the 4-sigma discrepancy between beam and bottle methods for neutron lifetime measurements. In order for BL3 to make a precise measurement of the neutron lifetime, the absolute neutron flux and proton rate will be measured. Thus, the BL3 experiment must have very efficient proton detection. We not only must understand the distribution of proton hits on the detector, we must also understand the interaction of the protons with silicon—namely, how the protons backscatter. We will discuss our systematic testing of detector position and implementation of a model for studying backscattering protons.