Search results for "nuclide"
showing 10 items of 397 documents
Geochemistry and isotope composition (Sr, Pb, δ66Zn) of Vulcano fumaroles (Aeolian Islands, Italy)
2018
We present and discuss temperatures, major and trace element gas geochemistry, radiogenic isotopes (Pb, Sr) and the first Zn isotope data of fumarole condensates and altered rocks from the Vulcano fumarolic field. The fumaroles of the La Fossa cone, sampled on 5th May 2015, have temperatures ranging between 233 and 427 °C. They plot compositionally on the mixing trend between the magmatic and hydrothermal end-members defined by previous studies, but are strongly displaced towards the hydrothermal component. Correlations of radiogenic (Sr, Pb) and stable isotopes of Zn with δ13CCO2 and several trace elements of the fumarolic acid condensates support mixing between the above mentioned distinc…
Natural and artificial radioactivity levels in Livingston Island (Antarctic regions).
1994
Radioactive contamination of the sea and land is due, on the one hand, to fallout from atmospheric atomic explosions since 1945, and, on the other, to emissions produced by nuclear and radioactive facilities. Given its geographic position far distant from the aforementioned main sources of radioactive contamination, Antarctica should have the lowest levels that can be measured on the Earth of artificial radionuclides in the various receptor media which are characteristic of the trophic chain. In the case of Antarctica, these are melt-water, sea-water, mosses, algae, and lichens. With the aim of contributing basic information on the radiation levels present in the Antarctic ecosystem, we hav…
On-Line Measurement of Gaseous Iodine Species During a PWR Severe Accident
2015
International audience; Iodine is a highly radio-toxic element, due to its affinity to the thyroid, and represents the major part of the radioactivity released during a nuclear accident. In the context of nuclear safety and radio-protection, we are interested in identifying the iodine gaseous species which are released, in the nuclear power plants, under molecular (I$_2$) and organic (CH$_3$I) forms. Therefore, we are working on providing a spectroscopic database for both species. While the infrared spectrum of the ν6 band of methyl iodide was previously studied, only 4000 lines were assigned. We present the rovibrational analysis of a high quality experimental spectrum, of this band, recor…
Lead isotopes of the carbonate-hosted Kabwe, Tsumeb, and Kipushi Pb-Zn-CU sulphide deposits in relation to Pan African orogenesis in the Damaran-Lufi…
1999
Lead isotope ratios of galena from the carbonate-hosted massive sulphide deposits of Kabwe (Pb-Zn) and Tsumeb (Pb-Zn-Cu) in Zambia and Namibia, respectively, have been measured and found to be homogeneous and characteristic of upper crustal source rocks. Kabwe galena has average isotope ratios of 206/204Pb = 17.997 ± 0.007, 207/204Pb = 15.713 ± 0.010 and 208/204Pb = 38.410 ± 0.033. Tsumeb galena has slightly higher 206/204Pb (18.112 ± 0.035) and slightly lower 207/204Pb (15.674 ± 0.016) and 208/204Pb (38.276 ± 0.073) ratios than Kabwe galena. The isotopic differences are attributed to local differences in the age and composition of the respective source rocks for Kabwe and Tsumeb. The homog…
Natural Radioactivity in Clay and Building Materials Used in Latvia
2015
Abstract This paper presents the results of natural radionuclide concentration and activity index study in materials used for construction in Latvia. Special attention is given to clay and clay ceramics. Concentrations of K-40 and Th- 232, U-238 radioactivity were determined using gamma-spectrometry method. In some building ware, maximal concentration of K-40 was 1440 Bq/kg, and of U-238 - 175 Bq/kg. In granite, the determined maximum concentration of Th-232 was 210 Bq/kg. It was found that radionuclide content in different period clay deposits can differ by more than two times, and up to five times in different clay ceramics. The results obtained are compared with analogous data from the o…
Modeling of 137Cs migration in soils using an 80-year soil archive: role of fertilizers and agricultural amendments
2008
An 80-year soil archive, the 42-plot experimental design at the INRA in Versailles (France), is used here to study long-term contamination by 137Cs atmospheric deposition and the fate of this radioisotope when associated with various agricultural practices: fallow land, KCl, NH4(NO3), superphosphate fertilizers, horse manure and lime amendments. The pertinence of a simple box model, where radiocaesium is supposed to move downward by convectional mechanisms, is checked using samples from control plots which had been neither amended, nor cultivated since 1928. This simple model presents the advantage of depending on only two parameters: α, a proportional factor allowing the historical atmosph…
Post-Processing via Cation Exchange Cartridges: Versatile Options
2012
New 68Ge/68Ga radionuclide generators provide the positron emitter 68Ga (T½ = 67.7 min) as an easily available and relatively inexpensive source of a PET nuclide for labeling of interesting targeting vectors. However, currently available “ionic” 68Ge/68Ga radionuclide generators are not necessarily optimized for the routine synthesis of 68Ga-labeled radiopharmaceuticals in a clinical environment. Post-processing of 68Ge/68Ga generators using cation exchange resins provides chemically and radiochemically pure 68Ga with 97±2% within less than 4 min, with 68Ge almost completely removed, and ready for online labeling. This simple, fast, and efficient technology can be extended for new applicati…
The Renaissance of the 68Ge/68Ga Radionuclide Generator Initiates New Developments in 68Ga Radiopharmaceutical Chemistry
2010
⁶⁸Ge/⁶⁸Ga radionuclide generators have been investigated for almost fifty years now, since the cyclotron-independent availability of positron emitting ⁶⁸Ga via the ⁶⁸Ge/⁶⁸Ga system had always attracted researches working in basic nuclear chemistry as well as radiopharmaceutical chemistry. However, it took decades and generations of research (and researchers) to finally approach a reliable level of ⁶⁸Ge/⁶⁸Ga generator designs, adequate to the modern requirements of radiometal labeling chemistry. ⁶⁸Ga radiopharmacy now is awaking from a sort of hibernation. The exciting perspective for the ⁶⁸Ge/⁶⁸Ga generator, now - more than ever, asks for systematic chemical, radiochemical, technological an…
Improved column-based radiochemical processing of the generator produced 68Ga.
2011
An improved chemical strategy for processing of the generator produced (68)Ga was developed based on processing of the original (68)Ge/(68)Ga generator eluate on a micro-column. Direct pre-concentration and purification of the eluted (68)Ga is performed on a cation-exchange resin in hydrochloric acid/acetone media. A supplementary step based on a second micro-column filled with a second resin allows direct re-adsorption of (68)Ga eluted from the cation exchanger. (68)Ga is finally striped from the second resin with a small volume of pure water. For this purpose a strong anion exchanger and a novel extraction chromatographic resin based on tetraalkyldiglycolamides are characterized. The stra…
Depth profiling of Pu, 241Am and 137Cs in soils from southern Belarus measured by ICP-MS and alpha- and gamma-spectrometry
2003
The depth distribution of plutonium, americium, and Cs-137 originating front the 1986 accident at the Chernobyl Nuclear Power Plant (NPP) was investigated in several soil profiles in the vicinity from Belarus. The vertical migration of transuranic elements in soils typical of the 30 km relocation area around Chernobyl NPP was studied using inductively coupled plasma mass spectrometry (ICP-MS), alpha spectrometry, and gamma spectrometry. Transuranic concentrations in upper soil layers ranged from 6 x 10(-12) g g(-1) to 6 x 10(-10) g g(-1) for plutonium and from 1.8 x 10(-13) g g(-1) to 1.6 x 10(-11) g g(-1) for americium. These concentrations correspond to specific activities of Pu239+240 of…