Performances and stability of a 2.4 ton Gd organic liquid scintillator target for antineutrino detection

TL;DR

This paper reports on the performance, stability, and properties of a 2.4-ton Gd-doped organic liquid scintillator target used for antineutrino detection, demonstrating long-term stability over two years.

Contribution

It presents the largest stable Gd-doped organic liquid scintillator target with detailed monitoring over two years, showing no degradation or instability.

Findings

Gd and fluor concentrations remained stable over 2 years

Optical and fluorescent properties showed no degradation

Neutron detection efficiency remained consistent

Abstract

In this work we report the performances and the chemical and physical properties of a (2 x 1.2) ton organic liquid scintillator target doped with Gd up to ~0.1%, and the results of a 2 year long stability survey. In particular we have monitored the amount of both Gd and primary fluor actually in solution, the optical and fluorescent properties of the Gd-doped liquid scintillator (GdLS) and its performances as a neutron detector, namely neutron capture efficiency and average capture time. The experimental survey is ongoing, the target being continuously monitored. After two years from the doping time the performances of the Gd-doped liquid scintillator do not show any hint of degradation and instability; this conclusion comes both from the laboratory measurements and from the "in-tank" measurements. This is the largest stable Gd-doped organic liquid scintillator target ever produced and continuously operated for a long period.