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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.
Amano, Hikaru; Onuma, Yoshikazu*
Journal of Radioanalytical and Nuclear Chemistry, 255(1), p.217 - 222, 2003/01
Times Cited Count:8 Percentile:49.8(Chemistry, Analytical)no abstracts in English
Tochiyama, Osamu*
JNC TJ8400 2000-044, 53 Pages, 2000/02
To estimate the polyelectrolyte effect and the effect of the heterogeneous composition of humic acids, the complex formation constants of Eu(III) and Ca(II) with Aldrich humic acid and polyacrylic acid were obtained, for Eu(10 to 10 M) by solvent extraction with TTA and TBP in xylene, for Ca (10M) with TTA and TOPO in cyclohexane and for Ca(10M) by using ion-selective electrode. By defining the apparent formation as = [MR]/([M][R]), where [R] denotes the concentration of dissociated functional group, [M] and [MR] denote the concentration of free and bound metal ion and pcH is defined as-log[H], the values of log have been obtained at pcH 4.8 - 5.5 in 0.1 - 1.0M NaClO and NaCl. Log of Eu-humate varied from 5.0 to 9.3 and that of Ca-humate from 2.0 to 3.4..For both humate and polyacrylate, log increased with pcH or with the degree of dissociation. The increase in the ionic strength O.1 to 1.0 M decreased the log, the decrease in log of Eu(III)-humate is 1.6, that of Eu(III), polyacrylate 0.7, that of Ca(II)-humate 1.9 and that of Ca(II)-polyacrylate 1.2. While the increase in the metal ion produced no effect on log of polyacrylate, log of humate decreased. Depending on the concentration of Eu(III), the coexistence of Ca(II) reduced log of humate by 0 to 0.8. The dependence of log of humate on the metal ion concentration suggests the coexistence of strong and weak binding sites in the hmnic acid.
Amano, Hikaru; Ueno, Takashi; Arkhipov, N.*; Paskevich, S.*; Onuma, Yoshikazu*
Proceedings of 10th International Congress of the International Radiation Protection Association (IRPA-10) (CD-ROM), 6 Pages, 2000/00
no abstracts in English
Amano, Hikaru; Matsunaga, Takeshi; Ueno, Takashi; Yanase, Nobuyuki; Nagao, Seiya
Proceedings of the 2nd ISTC/SAC Seminar "Large Scale Area Remediation", p.2_75 - 2_81, 1999/00
no abstracts in English
Amano, Hikaru; Matsunaga, Takeshi; Ueno, Takashi; Onuma, Yoshikazu*; Watanabe, Miki*; Yanase, Nobuyuki; Nagao, Seiya; Sukhoruchkin, A. K.*
Proceedings of 5th International Scientific and Technical Conference on the Problems of Liquidation of Chernobyl Accident Consequences, P. 74, 1996/00
no abstracts in English