Concentrations of 127I and 129I in rainwater samples from several stations across Argentina (lati... more Concentrations of 127I and 129I in rainwater samples from several stations across Argentina (latitudes between 25° S and 55° S) were measured and analyzed for the assessment of distribution patterns and potential sources of 129I in the Southern Hemisphere. Measured 129I levels, clearly above those explainable by natural background and atmospheric nuclear weapons tests, can be understood by the injection into the Southern Hemisphere of 129I that had been discharged from nuclear fuel reprocessing plants in the Northern Hemisphere.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2008
The nucleogenic isotopes 36Cl, 236U and 239Pu are produced naturally in subsurface environments v... more The nucleogenic isotopes 36Cl, 236U and 239Pu are produced naturally in subsurface environments via neutron capture of thermal and epithermal neutrons. Concentrations are, however, very low and accelerator mass spectrometry (AMS) is required for quantitative measurements. A particular challenge is presented by the measurement of 236U/238U ratios down to the level of 10−13 that is expected from rocks with low
Geological Society, London, Special Publications, 2014
Atmospheric testing of nuclear weapons during the period 1945–1980 ushered in the ‘atomic age’ an... more Atmospheric testing of nuclear weapons during the period 1945–1980 ushered in the ‘atomic age’ and released large quantities of anthropogenic radiogenic nuclides into the atmosphere. These radionuclides were subsequently deposited as fallout to the entire surface of the planet. While many have decayed to negligible levels, long-lived radionuclides persist and will do so for thousands of years. Isotopes of plutonium, 239Pu (half-life 24 100 years) and 240Pu (half-life 6563 years), provide the best chronological markers for the onset of this anthropogenic event both now and into the future due to their long half-lives, particle-reactivity, and the fact that they were present in negligible quantities prior to anthropogenic production and release. Chronostratigraphic markers established by distinct Pu concentration profiles and Pu isotope changes in sediment sequences and ice and coral cores can provide high-resolution dating over the last 60 years. However, even though fallout has ceas...
National Key Research and Development Program (2016YFA0600502) National Natural Science Foundatio... more National Key Research and Development Program (2016YFA0600502) National Natural Science Foundation of China (41671466, 41773004).
Concentrations of 127I and 129I in rainwater samples from several stations across Argentina (lati... more Concentrations of 127I and 129I in rainwater samples from several stations across Argentina (latitudes between 25° S and 55° S) were measured and analyzed for the assessment of distribution patterns and potential sources of 129I in the Southern Hemisphere. Measured 129I levels, clearly above those explainable by natural background and atmospheric nuclear weapons tests, can be understood by the injection into the Southern Hemisphere of 129I that had been discharged from nuclear fuel reprocessing plants in the Northern Hemisphere.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2008
The nucleogenic isotopes 36Cl, 236U and 239Pu are produced naturally in subsurface environments v... more The nucleogenic isotopes 36Cl, 236U and 239Pu are produced naturally in subsurface environments via neutron capture of thermal and epithermal neutrons. Concentrations are, however, very low and accelerator mass spectrometry (AMS) is required for quantitative measurements. A particular challenge is presented by the measurement of 236U/238U ratios down to the level of 10−13 that is expected from rocks with low
Geological Society, London, Special Publications, 2014
Atmospheric testing of nuclear weapons during the period 1945–1980 ushered in the ‘atomic age’ an... more Atmospheric testing of nuclear weapons during the period 1945–1980 ushered in the ‘atomic age’ and released large quantities of anthropogenic radiogenic nuclides into the atmosphere. These radionuclides were subsequently deposited as fallout to the entire surface of the planet. While many have decayed to negligible levels, long-lived radionuclides persist and will do so for thousands of years. Isotopes of plutonium, 239Pu (half-life 24 100 years) and 240Pu (half-life 6563 years), provide the best chronological markers for the onset of this anthropogenic event both now and into the future due to their long half-lives, particle-reactivity, and the fact that they were present in negligible quantities prior to anthropogenic production and release. Chronostratigraphic markers established by distinct Pu concentration profiles and Pu isotope changes in sediment sequences and ice and coral cores can provide high-resolution dating over the last 60 years. However, even though fallout has ceas...
National Key Research and Development Program (2016YFA0600502) National Natural Science Foundatio... more National Key Research and Development Program (2016YFA0600502) National Natural Science Foundation of China (41671466, 41773004).
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