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Sr and 
Cs by AMSHonda, Maki; Martschini, M.*; Wieser, A.*; Marchhart, O.*; Lachner, J.*; Priller, A.*; Steier, P.*; Golser, R.*; Sakaguchi, Aya*
JAEA-Conf 2022-001, p.85 - 90, 2022/11
Accelerator mass spectrometry (AMS) is an analytical method that combines mass spectrometry with a tandem accelerator, which has been used mainly in nuclear physics experiments. AMS is used to measure radionuclides with half-lives of 10
-10
years. For radionuclides with half-lives of this order, the method of measuring their mass is 10-10
times more sensitive than measuring their activity. Because of this advantage, AMS has been widely applied in Earth and planetary sciences, atomic energy research, and other fields. Among the various studies, Wallner et al. (2021, 2016) have achieved excellent work in Earth and planetary sciences. For example, they have attained the ultra-sensitive analysis of 
Fe and 
Pu in environmental samples. These are radionuclides produced by rapid-neutron-capture (r-process) nucleosynthesis. Our recent work shows that a new AMS system (VERA, University of Vienna), which combines laser isobaric separation and a typical AMS system, has been successfully applied to the ultra-sensitive determination of Sr and Cs in environment. For Sr in environmental samples, the 
-ray measurement by the milking of the daughter nuclide Y is still the principal method, which takes 3-6 weeks. The new AMS method has a detection limit of 
0.1 mBq, which is comparable to that of -ray measurement, with a more straightforward chemical treatment than -measurement. Our achievement demonstrates that AMS can be a practical new method for determining Sr in the environment.
Hain, K.*; Martschini, M.*; G
lce, F.*; Honda, Maki; Lachner, J.*; Kern, M.*; Pitters, J.*; Quinto, F.*; Sakaguchi, Aya*; Steier, P.*; et al.
Frontiers in Marine Science (Internet), 9, p.837515_1 - 837515_17, 2022/03
Times Cited Count：11 Percentile：96.12(Environmental Sciences)Recent major advances in accelerator mass spectrometry (AMS) at the Vienna Environmental Research Accelerator (VERA) regarding detection efficiency and isobar suppression have opened possibilities for the analysis of additional long-lived radionuclides at ultra-low environmental concentrations. These radionuclides, including 
U, Cs, 
Tc and Sr, will become important for oceanographic tracer application due to their generally conservative behavior in ocean water. In particular, the isotope ratios U/
U and 
Cs/Cs have proven to be powerful fingerprints for emission source identification as they are not affected by elemental fractionation. Improved detection efficiencies allowed us to analyze all major long-lived actinides, i.e. U, 
Np, 
Pu, 
Am as well as the very rare U, in the same 10 L water samples of an exemplary depth profile from the northwest Pacific Ocean. Especially for Sr analysis, our new approach has already been validated for selected reference materials (e.g. IAEA-A-12) and is ready for application in oceanographic studies. We estimate that a sample volume of only (1-3) L ocean water is sufficient for Sr as well as Cs analysis, respectively.
Duarte, A. G.*; Katata, Genki; Hoshika, Yasutomo*; Hossain, M.*; Kreuzwieser, J.*; Arneth, A.*; Ruehr, N. K.*
Journal of Plant Physiology, 205, p.57 - 66, 2016/10
Times Cited Count：35 Percentile：80.36(Plant Sciences)The frequency and intensity of climatic extremes, such as heat waves, are predicted to increase globally, with severe implications for terrestrial carbon and water cycling. Temperatures may rise above critical thresholds that allow trees to function optimally, with unknown long-term consequences for forest ecosystems. In this context, we investigated how photosynthetic traits and the water balance in Douglasfir are affected by exposure to three heat waves. Photosynthetic carboxylation efficiency was mostly unaffected, but electron transport and photosynthetic rates under saturating light were strongly influenced by the heat waves, with lagging limitations on photosynthesis still being observed six weeks after the last heat wave. We also observed lingering heat-induced inhibitions on transpiration, minimum stomatal conductance, and nighttime stomatal conductance. Results from the stomatal models used to calculate minimum stomatal conductance were similar to gs-night and indicated changes in leaf morphology, such as stomatal occlusions and alterations in epicuticular wax. Our results show Douglas-fir's ability to restrict water loss following heat stress, but at the price of reduced photosynthetic performance. Such limitations indicate potential long-term restrictions that heat waves can impose on tree development and functioning under extreme climatic conditions.
F.Coninckx*; A.Janett*; Kojima, Takuji; S.Onori*; M.Pantaloni*; H.Schoenbacher*; M.Tavlet*; Wieser, A.*
Applied Radiation and Isotopes, 47(11-12), p.1223 - 1229, 1996/00
Times Cited Count：5 Percentile：45.11(Chemistry, Inorganic & Nuclear)no abstracts in English
Sr and Cs AMSHonda, Maki; Martschini, M.*; Lachner, J.*; Marchhart, O.*; Wieser, A.*; Priller, A.*; Steier, P.*; Golser, R.*; Sakaguchi, Aya*
no journal, ,
We have developed new analytical methods forSr (28.79 yr) and Cs (2.3x10 yr) by accelerator mass spectrometry (AMS) for the further development of the research on the environmental fate of artificial radionuclidesSr and Cs (30.1 yr). The AMS method enables the analysis of trace amounts ofSr and Cs with a simple chemical separation procedure. Having a longer half-life Cs applies as a proxy for Cs. For Sr, SrF
targets were prepared from radioactive environmental reference materials with known Sr concentrations (IAEA) by a chemical separation procedure that takes about two days to complete. Sr measured by AMS at VERA, University of Vienna. As a result, a limit of detection of 0.1 mBq was obtained, which is comparable to the ray measurement. The detection of Sr in environmental samples was also successful, indicating that the Sr AMS can apply to environmental samples. On the other hand, there are still some technical challenges in the Cs AMS. Therefore, the experimental measurements are in progress.
Honda, Maki; Martschini, M.*; Lachner, J.*; Wieser, A.*; Marchhart, O.*; Steier, P.*; Golser, R.*; Sakaguchi, Aya*
no journal, ,
The effective isobar suppression system based on the interaction between accelerated ions and lasers (photons) has been introduced into conventional AMS systems, allowing an increasing number of nuclides to be measured by AMS. This presentation will give an overview of the analytical technique, the measurement results, and the remaining challenges as examples of world-leading successful AMS of Sr and Cs in environmental samples obtained from the IAEA and others. Moreover, the applicability of the AMS method in geoscience (e.g., studies of Sr distribution in the hydrosphere and the range of applicable environmental samples) will also be discussed.
