INVESTIGADORES
VIDAL Ricardo Alberto
artículos
Título:
Radiolysis of water ice in the outer solar system: Sputtering and trapping of radiation products
Autor/es:
D. A. BAHR; M. FAMÁ; R. A. VIDAL; R. A. BARAGIOLA
Revista:
JOURNAL OF GEOPHYSICAL RESEARCH
Editorial:
American Geophysical Union
Referencias:
Lugar: Washington, DC; Año: 2001 vol. 106 p. 33285 - 33290
ISSN:
0148-0227
Resumen:
We performed quantitative laboratory radiolysis experiments on cubic water ice
between 40 and 120 K, with 200 keV protons. We measured sputtering of atoms and
molecules and the trapping of radiolytic molecular species. The experiments were done at
fluences corresponding to exposure of the surface of the Jovian icy satellites to their
radiation environment up to thousands of years. During irradiation, O2 molecules are
ejected from the ice at a rate that grows roughly exponentially with temperature; this
behavior is the main reason for the temperature dependence of the total sputtering yield.
O2 trapped in the ice is thermally released from the ice upon warming; the desorbed flux
starts at the irradiation temperature and increases strongly above 120 K. Several peaks in
the desorption spectrum, which depend on irradiation temperature, point to a complex
distribution of trapping sites in the ice matrix. The yield of O2 produced by the 200 keV
protons and trapped in the ice is more than 2 orders of magnitude smaller than used in
recent models of Ganymede. We also found small amounts of trapped H2O2 that desorb
readily above 160 K.
readily above 160 K.
protons and trapped in the ice is more than 2 orders of magnitude smaller than used in
recent models of Ganymede. We also found small amounts of trapped H2O2 that desorb
readily above 160 K.
readily above 160 K.
starts at the irradiation temperature and increases strongly above 120 K. Several peaks in
the desorption spectrum, which depend on irradiation temperature, point to a complex
distribution of trapping sites in the ice matrix. The yield of O2 produced by the 200 keV
protons and trapped in the ice is more than 2 orders of magnitude smaller than used in
recent models of Ganymede. We also found small amounts of trapped H2O2 that desorb
readily above 160 K.
readily above 160 K.
protons and trapped in the ice is more than 2 orders of magnitude smaller than used in
recent models of Ganymede. We also found small amounts of trapped H2O2 that desorb
readily above 160 K.
readily above 160 K.
ejected from the ice at a rate that grows roughly exponentially with temperature; this
behavior is the main reason for the temperature dependence of the total sputtering yield.
O2 trapped in the ice is thermally released from the ice upon warming; the desorbed flux
starts at the irradiation temperature and increases strongly above 120 K. Several peaks in
the desorption spectrum, which depend on irradiation temperature, point to a complex
distribution of trapping sites in the ice matrix. The yield of O2 produced by the 200 keV
protons and trapped in the ice is more than 2 orders of magnitude smaller than used in
recent models of Ganymede. We also found small amounts of trapped H2O2 that desorb
readily above 160 K.
readily above 160 K.
protons and trapped in the ice is more than 2 orders of magnitude smaller than used in
recent models of Ganymede. We also found small amounts of trapped H2O2 that desorb
readily above 160 K.
readily above 160 K.
starts at the irradiation temperature and increases strongly above 120 K. Several peaks in
the desorption spectrum, which depend on irradiation temperature, point to a complex
distribution of trapping sites in the ice matrix. The yield of O2 produced by the 200 keV
protons and trapped in the ice is more than 2 orders of magnitude smaller than used in
recent models of Ganymede. We also found small amounts of trapped H2O2 that desorb
readily above 160 K.
readily above 160 K.
protons and trapped in the ice is more than 2 orders of magnitude smaller than used in
recent models of Ganymede. We also found small amounts of trapped H2O2 that desorb
readily above 160 K.
readily above 160 K.