Comparing Monte Carlo Simulations for Neutron Beta Decay Experiments*

Precise measurements of free neutron beta decay can result in the calculation of the CKM matrix element V_ud which can test the unitarity of the Standard Model. We can calculate V_ud using results from the Nab and BL3 experiments: the decay parameter λ and the neutron lifetime τ respectively. The current directive of BL3 is to account for the ~4σ discrepancy between the beam and bottle methods in the measurement of the neutron lifetime.

Both the Nab and BL3 experiments use silicon detectors to detect the decay products of neutron beta decay. IMSIL is a simulation tool for simulating the interaction of an ion beam with a target (crystal lattice); handling several aspects of detector physics such as backscattering and proton channeling, of which other simulation tools do not. In this presentation, I will give visual representations, as well as interpretations of IMSIL and Geant4 simulations. The primary motivation of this project is to compare the detector simulation results between IMSIL and Geant4, to determine if channeling plays a significant role in our simulation's predictions. This will allow us to study systematic effects through our simulation for Nab and BL3.