Development of Zr-loaded green-emitting liquid scintillator for detection of neutrinoless double beta decay

Abstract

In this study, zirconium acetylacetonate (Zr(acac)4) containing the isotope 96Zr was studied as a liquid scintillator for the possible detection of neutrinoless double beta decay. To avoid the absorption of scintillation by ligand absorption, the phosphor Coumarin 7 was assessed as a green-emitting liquid scintillator. By dissolving 3 g/L of Coumarin 7 in anisole, a liquid scintillator with a light yield of 12000 photons/MeV was fabricated. Subsequently, the liquid scintillator was loaded with Zr(acac)4. In the liquid scintillator containing 10 wt% Zr(acac)4, the light yield of scintillation was 370 photons/MeV for a blue-emitting liquid scintillator, while a light yield of 1900 photons/MeV was determined for a green-emitting liquid scintillator. The scintillation decay time constants of the fast component were around 4.4 ns. Liquid scintillators with a high light yield that avoid absorption by Zr(acac)4 can be prepared using Coumarin 7.