Speaker
Description
Liquid scintillation is a well-established technique for the detection and measurement of radiation, particularly effective for low-energy beta radiation and low-intensity alpha emitters. This method relies on converting the energy of ionizing particles, into light that are subsequently detected by photodetectors. Various applications use liquid scintillators, including medical diagnostics, nuclear research, security and industrial fields. Liquid scintillators consist of an organic solvent combined with primary and secondary fluorophores to maximize energy-to-light conversion efficiency according to the photodetectors. The ideal liquid scintillator must exhibit chemical stability, a high flash point, low volatility, and low toxicity. However, commonly used solvents like toluene, xylene, and more recently, di-isopropylnaphthalene and phenylxylylethane, do not fully meet these criteria. As a result, these scintillators must be sealed or cannot be used in high volume, for safety concerns and environmental challenges.
Research is currently focused on developing safer formulations, including alternative solvents, aqueous mixtures, and environmentally friendly scintillators but until now, the results presented in literature show inferior scintillation properties. Despite these limitations, liquid scintillators have certain advantages over plastic scintillators, such as good radiation hardness, low impurity levels, and greater scalability.
Our work focuses on an innovative new class of solvent-free liquid scintillators, based on an organic eutectic mixture. These eutectics contain several solid organic compounds with individual relatively high melting points (between 68°C and 76°C), lowered at 4°C when mixed solution. The organic molecules used in our work are well known for their scintillation properties; however, their combination has led to the unexpectedly results of a new liquid scintillator. Our solvent-free liquid scintillators exhibit huge benefits, including a high flash point, non-volatility, and non-flammability. This new class of liquid scintillators still at the very first stage of development and we are continuously exploring different formulation and molecules of interest. To highlight this fact, we present here four different mixtures of eutectics liquid scintillators and their full radio physical characterization. Among them our best candidates achieves Light yields of 9.700 ph/MeV. We also performed fast neutron/gamma discrimination with remarkable FoM values of 2.4 comparable to commercial standard BC501A (FoM 2.8).
This discovery and its results represent a new and previously unknown class of solvent-free liquid scintillator with great potential. These scintillators enable effective neutron-gamma discrimination in small volumes and contain no flammable or volatile solvents, making them safer for both production and use.
Acknowledgments:
This project has received funding from the French NRBC-E research program.
