Synthesis and Characterization of Lithium Carboxylates for Use in Lithium-Loaded Liquid Scintillator*

Lithium-6 can be used for neutron tagging in scintillator-based detectors due to its large neutron capture cross-section and Q-value of the neutron capture reaction. One method for incorporating lithium-6 into organic liquid scintillator utilizes aqueous solutions of enriched lithium emulsified within the scintillator by surfactants. However, at lithium-loading fractions above a few percent by mass, emulsions can undergo phase instabilities resulting in poor optical performance. An alternative loading method involving the direct dissolution of organic lithium salts into liquid organic scintillator may circumvent the deleterious effects of emulsification. We discuss the synthesis of several lithium carboxylates and their properties when loaded into the commercial liquid scintillator cocktail Ultima Gold AB and a comparable formulation without surfactants. Performance of carboxylates was analyzed in terms of solubility and light transmittance properties via UV-Vis spectroscopy.