Detection System for Neutron ${\hat{I}}^2$ Decay Correlations in the UCNB and Nab experiments

Abstract

We describe a detection system designed for precise measurements of angular correlations in neutron ${\hat{I}}^2$ decay. The system is based on thick, large area, highly segmented silicon detectors developed in collaboration with Micron Semiconductor, Ltd. The prototype system meets specifications for ${\hat{I}}^2$ electron detection with energy thresholds below 10 keV, energy resolution of $\sim$3 keV FWHM, and rise time of $\sim$50 ns with 19 of the 127 detector pixels instrumented. Using ultracold neutrons at the Los Alamos Neutron Science Center, we have demonstrated the coincident detection of ${\hat{I}}^2$ particles and recoil protons from neutron ${\hat{I}}^2$ decay. The fully instrumented detection system will be implemented in the UCNB and Nab experiments, to determine the neutron ${\hat{I}}^2$ decay parameters $B$, $a$, and $b$.

Copyright 2016. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/