You already have references to work by the Quickenden group but perhaps not the most recent one (Kinetics and Catalysis 2006, 47, 709-712 - I can send you a pdf), which might provide you with some others of use.
M. D. Tarasov et al, 'Efficiency of Radioluminescence of Water under the Action of Accelerated Electrons', Instruments and Experimental Techniques, 2007