Large solubility of Lithium carboxylates reaching high rates of 6Li incorporation in polystyrene-based plastic scintillators for fast/thermal neutrons and gamma rays detection

6Li-doped plastic scintillators (PSs) have been optimized as radioluminescent sensors for fast/thermal neutrons and gamma rays detection in a crucial terrorist threat context. Among 16 low molecular weight (C<8) lithium carboxylates, Liα-valerate (LiαVal) exhibits a high potential for loading (up to 50 wt%) in clear PSs composed of polystyrene and standard fluors (20 wt% PPO, 0.03 wt% POPOP). A methodical study of PS composition illustrates the Li carboxylates and methacrylic acid comonomers impacts on scintillation yields (from 4410 to 7790 ph/MeV) and nthermal/nfast/gamma discrimination performances with significant figures of merit (from 0.23 to 1.45).