High purity H2O ice at 88 K was excited by a nanosecond pulsed 0.5 MeV electron beam and was examined for luminescence emission in the wavelength range 200ndash;600 nm. Emission was observed in the three regions 280ndash;300 nm (Gp= 1times;10minus;7photons/100 eV), 340ndash;460 nm (GP= 2times;10minus;4photons/100 eV), and 500ndash;600 nm (Gp= 1times;10minus;5photons/100 eV). No single previous paper has reported emission from all of these three regions in H2O ice. A weak emission band observed at 230 nm by one previous worker was not observed in the present investigation. The overall luminescence yield of (2.4plusmn;0.6)times;10minus;4photons/100 eV lay in between the only two previous estimates of 2times;10minus;3and 9times;10minus;5photons/100 eV. Measurements on ice made from water which had been in contact with typical sources of impurity, indicated that impurities were unlikely sources of the luminescence. The luminescence between 310 and 550 nm showed a marked dependence on total accumulated dose, and the dependence conformed to the predictions of a model based on the competitive trapping of a single radiation produced species, by luminescent and nonluminescent reaction centers.
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