ISOTOPE EFFECTS IN THE 77 K GAMMA-IRRADIATION OF ICE.
Abstract
The radiation yields of H2, D2, and HD obtained by the 77 K gamma-irradiation of solute free mixed H2O and D2O ice mixtures have been determined by use of mass spectroscopy. The total gas yields have been determined, too, both by use of a calibrated mass spectrometer and by manometric methods. Significant isotope effects were observed over a wide range of isotopic compositions studied (i.e., the deuterium content varied from 0.016 to 99.8%). The separation factor alpha G = (H/D)gas/(H/D)ice varied from ca 70 for the high D content ice to ca 1.0 for natural isotopic abundance ice. At (H/D)ice = 1.0, alpha G is 1.7. Values of alpha G were obtained for 99.8% D2O over a temperature range of 4.2 to 196 K. The separation factor was found to be inversely proportional to temperature. The results of this study are compared with those in a previously published EPR study of stabilized H and D atoms after irradiation at 4.2 K. The observed effects are discussed briefly in terms of several models of selective energy absorption. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1966
- Accession Number
- AD0489782
Entities
People
- Robert Rennick
- Seymour Siegel
Organizations
- The Aerospace Corporation