A new hybrid gadolinium nanoparticles-loaded polymeric material for neutron detection in rare event searches

TL;DR

This paper presents the development and characterization of a novel hybrid polymeric material loaded with gadolinium nanoparticles, designed to improve neutron detection for dark matter experiments by combining high neutron capture cross-section with effective moderation.

Contribution

The paper introduces a new gadolinium nanoparticle-loaded polymeric material for neutron detection, detailing its fabrication, properties, and potential application in dark matter searches.

Findings

Successful creation of a gadolinium nanoparticle-loaded PMMA material

Material exhibits high neutron capture capability

Mechanical and purification properties characterized

Abstract

Experiments aimed at direct searches for WIMP dark matter require highly effective reduction of backgrounds and control of any residual radioactive contamination. In particular, neutrons interacting with atomic nuclei represent an important class of backgrounds due to the expected similarity of a WIMP-nucleon interaction, so that such experiments often feature a dedicated neutron detector surrounding the active target volume. In the context of the development of DarkSide-20k detector at INFN Gran Sasso National Laboratory (LNGS), several R&D projects were conceived and developed for the creation of a new hybrid material rich in both hydrogen and gadolinium nuclei to be employed as an essential element of the neutron detector. Thanks to its very high cross-section for neutron capture, gadolinium is one of the most widely used elements in neutron detectors, while the hydrogen-rich material is instrumental in efficiently moderating the neutrons. In this paper results from one of the R&Ds are presented. In this effort the new hybrid material was obtained as a poly(methyl methacrylate) (PMMA) matrix, loaded with gadolinium oxide in the form of nanoparticles. We describe its realization, including all phases of design, purification, construction, characterization, and determination of mechanical properties of the new material.