The tubs were exposed to the proton beam for consecutive fillings of water, WbLS-1, WbLS-2, and LS. Two 2x2x0.5 cm plastic scintillator hodoscopes were used to define the beam.

A 400 nm LED was placed just above each scintillating volume in Detector A to permit an in-situ single photoelectron PMT calibration. The low energy water irradiations were used for single photoelectron PMT calibrations in Detector B.

All samples were investigated using proton beams with incident energies of 475 MeV and 2 GeV at the NASA Space Radation Laboratory at Brookhaven National Laboratory. A 210 MeV incident proton beam was additionally used to investigate all samples in Detector B. The beam intensity at all energies was made low enough that the probability of having more than a single proton incident per accelerator bunch was small. An analysis of our results where the two-proton events are separable from the 1 proton events indicates that the fraction of two-proton events varied as a function of beam energy and was less than 10% in all irradiations. We have estimated the influence of the two-proton events by resampling the simulated single proton distributions presented below. Double proton events have no effect on the results with 