Honda, 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.
Honda, Maki; Martschini, M.*; Marchhart, O.*; Priller, A.*; Steier, P.*; Golser, R.*; Sato, Tetsuya; Tsukada, Kazuaki; Sakaguchi, Aya*
Analytical Methods, 14(28), p.2732 - 2738, 2022/07
The sensitive Sr analysis with accelerator mass spectrometry (AMS) was developed for the advances of environmental radiology. One advantage of AMS is the ability to analyze various environmental samples with Sr/Sr atomic ratios of 10 in a simple chemical separation. Three different IAEA samples with known Sr concentrations (moss-soil, animal bone, Syrian soil: 1 g each) were analyzed to assess the validity of the chemical separation and the AMS measurement. The Sr measurements were conducted on the AMS system combined with the Ion Laser InterAction MasSpectrometry (ILIAMS) setup at the University of Vienna, which has excellent isobaric separation performance. The isobaric interference of Zr in the Sr AMS was first removed by chemical separation. The separation factor of Zr in two-step column chromatography with Sr resin and anion exchange resin was 10. The Zr remaining in the sample was removed by ILIAMS effectively. This simple chemical separation achieved a limit of detection 0.1 mBq in the Sr AMS, which is lower than typical -ray detection. The agreement between AMS measurements and nominal values for the Sr concentrations of IAEA samples indicated that the new highly-sensitive Sr analysis in the environmental samples with AMS is reliable even for high matrix samples of soil and bone.
Hain, K.*; Martschini, M.*; Glce, 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
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.
Povinec, P. P.*; Aoyama, Michio*; Biddulph, D.*; Breier, R.*; Buesseler, K. O.*; Chang, C. C.*; Golser, R.*; Hou, X. L.*; Jekovsk, M.*; Jull, A. J. T.*; et al.
Biogeosciences, 10(8), p.5481 - 5496, 2013/08
Radionuclide impact of the Fukushima Dai-ichi Nuclear Power Plant accident on the distribution of radionuclides in seawater of the NW Pacific Ocean is compared with global fallout from atmospheric tests of nuclear weapons. Surface and water column seawater samples collected during the international expedition in June 2011 were analyzed for Cs, Cs, I and H. The Cs, I and H levels in surface seawater offshore Fukushima varied between 0.002-3.5 Bq/L, 0.01-0.8 Bq/L, and 0.05-0.15 Bq/L, respectively. At the sampling site about 40 km from the coast, where all three radionuclides were analyzed, the Fukushima impact on the levels of these three radionuclides represent an increase above the global fallout background by factors of about 1000, 30 and 3, respectively. The water column data indicate that the transport of Fukushima-derived radionuclides downward to the depth of 300 m has already occurred. The observed Cs levels in surface waters and in the water column are in reasonable agreement with predictions obtained from the Ocean General Circulation Model, which indicates that the radionuclides have been transported from the Fukushima coast eastward. Due to a suitable residence time in the ocean, Fukushima-derived radionuclides will provide useful tracers for isotope oceanography studies on the transport of water masses in the NW Pacific Ocean.
Honda, Maki; Martschini, M.*; Marchhart, O.*; Priller, A.*; Steier, P.*; Golser, R.*; Sakaguchi, Aya*; Sueki, Keisuke*
no journal, ,
no abstracts in English
Honda, 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.*; Marchhart, O.*; Steier, P.*; Golser, R.*; Sakaguchi, Aya*
no journal, ,
Accelerator mass spectrometry (AMS) is a relatively new analytical chemistry in applied research utilizing accelerators. In Japan, AMS has been used to measure C, which is applied for dating in archaeology, and Cl, which is used to assess the environmental effects of the disposal of radioactive waste from nuclear power plants and accelerator facilities. In recent years, conventional AMS systems have been combined with new analytical chemistry techniques to separate isobars, such as laser photo-detachment, leading to improved performance and the possibility of measuring new nuclides in AMS. This presentation will mainly focus on developing a highly sensitive Sr analysis technique utilizing the laser photo-detachment method equipped in the 3MV AMS at the University of Vienna. Furthermore, the feasibility of Sr AMS at facilities in Japan will be discussed.
Honda, Maki; Martschini, M.*; Steier, P.*; Golser, R.*; Kanivets, V.*; Rahman, I. M. M.*; Yamasaki, Shinya*; Sakaguchi, Aya*
no journal, ,
A new analytical method for Sr utilizing accelerator mass spectrometry (AMS) achieved better detection limits (1/10 of 0.1 mBq) than conventional -ray detection methods. In order to demonstrate the applicability of the AMS method to environmental samples of various properties, the present study analyzed impurity-rich water samples collected from the cooling water supply ponds of the Chornobyl NPP. The Sr/Sr atomic ratio of the water samples (evaluated by -ray detection and ICP-MS), the expected detection limit, and the analysis method are reported in this meeting. Furthermore, the adaptability of the AMS method for Sr concentration (Bq/L) in water samples will be demonstrated by comparing the AMS method with the -ray detection method.
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.
Martschini, M.*; Honda, Maki; Merchel, S.*; Winkler, S.*; Golser, R.*
no journal, ,
The quantitative analysis of Sr is cumbersome and time-consuming because it is a pure -ray emitter. The detection limit of Sr by conventional accelerator mass spectrometry (AMS) methods is comparable to the typical detection limit of 3 mBq for -ray detection methods, mainly due to the interference of the isobaric Zr. The worldwide unique Ion Laser Interaction Mass Spectrometry (ILIAMS), performed at the University of Vienna, effectively removes Zr with a laser and reaction gases. Therefore, the detection limits of Sr is superior (0.1 mBq) to conventional AMS systems not equipped with such an ion-laser interaction isobaric removal system. In this study, Sr analysis in coral samples etc., an environmental sample under extreme conditions (e.g. low concentrations of Bq/g and limited sample volumes of grams), was tried. To lower the detection limit 0.1 mBq, Sr was purified (Sr carrier) from old age coral with almost no Sr contamination from atmospheric nuclear tests, chemical separation of environmental samples were conducted, and Sr was measured by AMS. The results showed that the detection limit of Sr achieved in the analysis was 0.03 mBq (Sr/Sr 510, 1/100 of the -ray detection methods). The detection limit achieved in this study corresponds to 2 ag of Sr in 1 mg of Sr target. The latest results of highly sensitive Sr analysis in small amounts of general environmental samples (coral, seawater, etc.) are mainly presented.