Abstract: Simulation of Silicon Detector Performance for the Nab Experiment

The Nab Experiment at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) will make precise measurements of unpolarized neutron beta decay by measuring the electron-neutrino correlation coefficient, a, and the Fierz interference term, b.  The experiment employs two silicon detectors within a long electromagnetic spectrometer in order to measure the electron’s energy and the proton’s momentum. The silicon detectors are constructed with a fine Al wire grid in order to increase conductivity on the junction side, and an electric field within the spectrometer is applied to accelerate the protons to an energy where they can be detected. The Nab experiment is currently being installed and benchmarked. We have conducted Geant4 simulation studies of how the presence of the wire grid and electric field affects the efficiency of the silicon detectors in detecting the electron and proton produced in the decay. We will present an overview of these simulation studies and report the results.