Evaluation of Gadolinium's Action on Water Cherenkov Detector Systems with EGADS

TL;DR

This paper evaluates the feasibility of using gadolinium in water Cherenkov detectors to improve neutron detection, demonstrating the EGADS system's capabilities for potential advancements in particle physics experiments.

Contribution

It presents the design, implementation, and milestones of the EGADS R&D program for gadolinium-enhanced water Cherenkov detectors, a novel technique for neutron tagging.

Findings

EGADS successfully demonstrates neutron tagging with Gd in a water Cherenkov detector.

Gd-doped water maintains transparency and detector performance.

The technique opens new physics opportunities in neutrino and proton decay research.

Abstract

Used for both proton decay searches and neutrino physics, large water Cherenkov (WC) detectors have been very successful tools in particle physics. They are notable for their large masses and charged particle detection capabilities. While current WC detectors reconstruct charged particle tracks over a wide energy range, they cannot efficiently detect neutrons. Gadolinium (Gd) has the largest thermal neutron capture cross section of all stable nuclei and produces an 8 MeV gamma cascade that can be detected with high efficiency. Because of the many new physics opportunities that neutron tagging with a Gd salt dissolved in water would open up, a large-scale R&D program called EGADS was established to demonstrate this technique's feasibility. EGADS features all the components of a WC detector, chiefly a 200-ton stainless steel water tank furnished with 240 photo-detectors, DAQ, and a water system that removes all impurities in water while keeping Gd in solution. In this paper we discuss the milestones towards demonstrating the feasibility of this novel technique, and the features of EGADS in detail.