Preparation, stability, and performance characteristics of a neutron-sensitive liquid scintillation cocktail

Liquid scintillants can form the basis for high-efficiency, uniform, self-healing, and inexpensive neutron- and neutrino-sensitive detectors. The addition of surfactant combinations into organic scintillants allows the accommodation of different neutron-capture dopants, including ⁶Li. Added as an aqueous salt, ⁶Li can be incorporated into nanoscale aqueous domains in a reverse micellar solution (microemulsion). We describe a series of studies aimed at determining the Li-loading capacity of several commercially available liquid scintillants. Using Compton spectrum quenching techniques and optical spectroscopy, we address optimal loading, long-term stability, absolute light yield, and pulse shape discrimination characteristics for an easily prepared cocktail with Li mass fraction (f_Li) of 1 %. We find that Li loading has minimal impact on quenching or micellar dynamics in comparison to other effects. The f_Li makes the cocktail appealing as a stand-alone neutron detector or for capturing neutrons produced by inverse beta decay (IBD) detection of antineutrinos.