Simulations of the nEDM@SNS light collection system efficiency

TL;DR

This paper presents simulation results for a light collection system in the nEDM@SNS experiment, demonstrating high efficiency, accurate event localization, and background rejection for neutron electric dipole moment detection.

Contribution

It introduces a novel simulation-based design of a scintillation light collection system optimized for nEDM@SNS with improved efficiency and background discrimination.

Findings

Average of 17 photoelectrons per event

Event location reconstructed within 3 cm accuracy

High detection efficiency of 95% with 1% variation

Abstract

A system for collecting the scintillation light produced by the capture process of ultra-cold neutrons (UCN) on polarized $^{3}$He is discussed and results from simulations of its performance are presented. This system will be implemented in nEDM@SNS, the experiment searching for the neutron electric dipole moment (nEDM) at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory. Simulation results show that the light collection system collects on average 17 photoelectrons per UCN-$^{3}$He capture event (sufficient to generate a robust signal), reconstructs the event location in the beam direction to approximately 3 cm accuracy, detects capture events with a high and spatially uniform efficiency (0.95 with 1% variation), and rejects greater than 50% of beta decay background events.