ICE NEAR 0-DEGREES-C - RADIOLYSIS AND ABSORBED DOSE CALORIMETRY

The production of H2O2 vs absorbed dose was measured for deaerated ice and H-2-saturated ice at -23, -10 and -0.8 degrees C. For the first t ime, the establishment of a steady state was demonstrated. The dose re quired to reach a steady state of 0.7-0.8 mu mol . dm(-3) H2O2 was abo ut 20 Gy in clear, annealed crystals at -0.8 and -10 degrees C. The st eady state concentration of H2O2 was about 70% higher in annealed ice than in freshly-frozen ice. 200-400 Gy was needed to reach a steady st ate concentration of 1.2 mu mol . dm(-3) H2O2 in cracked crystals at - 23 degrees C. In H-2-saturated ice at -23, -10 and -0.8 degrees C, H2O 2 reached a steady state concentration of about 0.2 mu mol . dm(-3) at less than 8 Gy. Ice near 0 degrees C, after pre-irradiation to a stea dy state, has a heat defect of zero which is a useful condition for ic e calorimetry. Crown Copyright (C) 1996 Published by Elsevier Science Ltd.