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Oral presentation

U-238 M$"o$ssbauer spectroscopic study of uranium oxysulfide

Masaki, Nobuyuki; Nakada, Masami; Akabori, Mitsuo; Arai, Yasuo; Nakamura, Akio; Sato, Nobuaki*

no journal, , 

The U-238 M$"o$ssbauer effect of uranium oxysulfide, UOS, has been investigated at various temperatures from 19 K to 80 K. The $$gamma$$-ray source used for U-238 M$"o$ssbauer spectroscopy was Pu-242 dioxide with high isotope purity. By using a pure Ge detector, the 44.9 keV U-238 M$"o$ssbauer $$gamma$$-ray is easily distinguished from the 59.5 keV $$gamma$$-ray of the Am-241 isotope, which is the daughter nucleus of the isotopic impurity Pu-241. Quadrupole splitting of the U-238 nucleus in UOS is approximately -40 mm/s in the temperature range without account of magnetic splitting. According to neutron diffraction and magnetic susceptibility measurements, UOS is antiferromagnetic at low temperatures with a Neel temperature of T$$_{N}$$ = 55 K. However, M$"o$ssbauer spectra below 55 K could be analyzed by using only quadrupole splitting without magnetic splitting. This result showed that the magnitude of quadrupole splitting was much larger than that of magnetic splitting of U nucleus in UOS.

Oral presentation

Cation-exchange behavior of Zr, Hf, and Th in H$$_{2}$$SO$$_{4}$$/HNO$$_{3}$$ mixed solutions; Towards to study on sulfate complexation of $$^{104}$$Rf

Li, Z.; Toyoshima, Atsushi; Tsukada, Kazuaki; Asai, Masato; Sato, Tetsuya; Kikuchi, Takahiro; Sato, Nozomi; Nagame, Yuichiro

no journal, , 

Oral presentation

Ion-exchange separation for accurate trace analysis of environmental samples for safeguards

Miyamoto, Yutaka; Yasuda, Kenichiro; Magara, Masaaki; Kimura, Takaumi

no journal, , 

For accurate isotopic analysis of trace uranium, chemical separation of tungsten from uranium and plutonium in environmental samples for safeguards with an anion-exchange column was investigated. The mixture of HCl and HF was appropriate for the elimination of tungsten from uranium, and this technique is applicable to the separation of uranium in environmental samples.

Oral presentation

Sequential ion-exchange separation and analysis of trace uranium, thorium, lead and lanthanides in environmental samples

Miyamoto, Yutaka; Yasuda, Kenichiro; Magara, Masaaki; Kimura, Takaumi

no journal, , 

Appropriate composition of eluents for sequential separation of trace U, Th, Pb and lanthanides with a single anion-exchange column was examined. The mixtures of acetic acid, hydrochloric acid and nitric acid made complete separation of the elements of interest. The elements in some reference materials were separated with this technique, and performance of this separation was evaluated.

Oral presentation

A Study of isotope ratio measurement of ultra-trace nuclear materials in environmental samples

Kokubu, Yoko

no journal, , 

no abstracts in English

Oral presentation

Improvement of $$^{14}$$C measurement by JAEA-AMS-TONO

Kokubu, Yoko; Nishizawa, Akimitsu*; Owaki, Yoshio*; Nishio, Tomohiro*; Suzuki, Mototaka; Ishimaru, Tsuneari

no journal, , 

no abstracts in English

Oral presentation

Rapid reductive preparation of Np(IV) based on the electrocatalytic reaction

Kitatsuji, Yoshihiro; Kimura, Takaumi; Kihara, Sorin*

no journal, , 

The behaviors of reduction of NpO$$_{2}$$$$^{+}$$ to Np$$^{4+}$$ or Np$$^{3+}$$ by controlled potential electrolysis were studied, and a unique time course of electrolysis current was observed. It was concluded that NpO$$_{2}$$$$^{+}$$ was reduced by two reduction processes at a platinum electrode: the chemical reaction with Np$$^{3+}$$ and the electrocatalytic reduction by adsorbed hydrogen atom on platinum electrode surface. NpO$$_{2}$$$$^{+}$$ is reduced to Np$$^{4+}$$ more selectively and with smaller overpotential through electrocatalytic reduction process, though long electrolysis time are required to reduce NpO$$_{2}$$$$^{+}$$ completely. To improve the electrolysis efficiency of the preparation of Np$$^{4+}$$ from NpO$$_{2}$$$$^{+}$$, the platinized platinum electrode was applied to bulk electrolysis. The rapid preparation of Np$$^{4+}$$ comparable to that of reversible redox reaction such as NpO$$_{2}$$$$^{2+}$$/ NpO$$_{2}$$$$^{+}$$ with small overpotential was achieved successfully.

Oral presentation

Selective adsorption of trivalent actinides to activated carbon

Arisaka, Makoto; Watanabe, Masayuki; Kimura, Takaumi

no journal, , 

Adsorption behaviors of trivalent actinides (An(III)) and lanthanides (Ln(III)) to activated carbons with and without oxidation by concentrated nitric acid were investigated. Both An(III) and Ln(III) was adsorbed to activated carbons in the range from pH 1 to 4, and the distribution coefficients (${it K}$ $$_{d}$$) of An(III) and Ln(III) increase with an increase of pH. Activated carbon without oxidation exhibits significant selectivity to An(III) compared with Ln(III). On the other hand, the oxidation to activated carbon deteriorates the selectivity to An(III). The depletion by the oxidation was attributed to the increase of functional groups of oxygen-donor, e.g., carboxyl and/or carbonyl groups because these functional groups are unfavorable for separation between An(III) and Ln(III). The selectivity of activated carbon without oxidation would be attributed to the interaction between $$pi$$-electrons of aromatic ring and the metal ions.

Oral presentation

On-line isothermal gas chromatographic behavior of group 5 elements Nb and Ta as homologues of Db

Sato, Tetsuya; Tsukada, Kazuaki; Asai, Masato; Toyoshima, Atsushi; Kasamatsu, Yoshitaka*; Li, Z.; Sato, Nozomi; Kikuchi, Takahiro; Nagame, Yuichiro

no journal, , 

To investigate chemical properties of the transactinide element dubnium (Db, Z=105), we have developed an on-line isothermal gas chromatographic apparatus. The on-line experiments with the group-5 elements using the short lived $$^{88}$$Nb and $${170}$$Ta as the homologues of Db were conducted. We measured the relative chemical yields of volatile compounds of $${88}$$Nb and $${170}$$Ta as a function of the isothermal temperature in chlorinating condition with mixture of air and the SOCl$$_2$$ vapor. It was found that the volatility of compounds of Ta is lower than that of Nb.

Oral presentation

Production of Lu-177 capable of labeling antibodies

Watanabe, Satoshi; Hashimoto, Kazuyuki; Watanabe, Shigeki; Iida, Yasuhiko*; Hanaoka, Hirofumi*; Endo, Keigo*; Ishioka, Noriko

no journal, , 

no abstracts in English

Oral presentation

Development of nitrogen compounds: N,N-Dialkyl-2-(1H-benzimidazol-2-yl)-pyridine-6-carboxamide and elucidation of their complexation toward f-element ions

Akutsu, Kazuhiro; Suzuki, Shinichi; Kobayashi, Toru; Shiwaku, Hideaki; Ikeda, Atsushi; Okamoto, Yoshihiro; Yaita, Tsuyoshi

no journal, , 

The separation of trivalent actinides from trivalent lanthanides is an important tasks for the facilitation of the management of high level radioactive waste. N,N-dialkyl-2-(1H-benzimidazol-2-yl)-pyridine-6-carboxamide (BIZA) derivatives, having a various length of alkyl groups, were synthesized as the extractant for the separation of An(III) from Ln(III). Their complexation behaviors with Ln(III) and extractability of Am(III) and Ln(III) were studied. Regarding the formation constants between Eu(III) and BIZA, BIZA with octyl group (octyl-BIZA) showed one-order smaller value than that with methyl group (methyl-BIZA). Additionally, the average bond distance of the N, O atoms of octyl-BIZA with Eu(III) was longer than that of methyl-BIZA. These differences might be due to a steric hindrance deriving from bulkiness of their substituent. Moreover, it is investigated that the MePh-BIZA can extract Am(III) selectively over Eu(III) and the distribution ratio of Am(III) is high.

Oral presentation

Analytical methods using a positron beam

Oka, Toshitaka

no journal, , 

Positrons have been used for material analysis. Positrons injected into a material annihilate with electrons and emit two annihilation $$gamma$$-rays. We can estimate microstructure and chemistry of the material by detecting these $$gamma$$-rays. In this presentation, the generation of positron beam and the analytical methods using position beam were introduced.

Oral presentation

Actinides extraction and complexation properties of new oxygen-nitrogen hetero donor ligand PTA

Kobayashi, Toru; Suzuki, Shinichi; Ikeda, Atsushi; Shiwaku, Hideaki; Okamoto, Yoshihiro; Akutsu, Kazuhiro; Yaita, Tsuyoshi

no journal, , 

The development of actinides recognition compound is of increasing importance because it concerns separation techniques in nuclear fuel cycle and/or decontamination of radioactive waste. In this study, we have developed novel oxygen-nitrogen hetero donor ligand PTA, which includes two aza-aromatic donors and an oxygen donor in a single molecule, and investigated actinides extraction properties of this ligand. As a result, it is revealed that PTA shows high extractability and selectivity for actinides over lanthanides even in the acid condition. Furthermore, investigations of complexation properties and speciation by X-ray crystallography, EXAFS and spectroscopic titration revealed that the presence of an oxygen donor in the PTA significantly promotes binding between the ligand and metal ion even in acidic conditions.

Oral presentation

Production and decay properties of $$^{266}$$Bh and its daughter nuclei

Morimoto, Koji*; Morita, Kosuke*; Kaji, Daiya*; Haba, Hiromitsu*; Ozeki, Kazutaka*; Kudo, Yuki*; Sato, Nozomi; Sumita, Takayuki*; Yoneda, Akira*; Ichikawa, Takatoshi*; et al.

no journal, , 

no abstracts in English

Oral presentation

Productions and decay properties of a new isotope of $$^{263}$$Hs

Kaji, Daiya*; Morimoto, Koji*; Sato, Nozomi; Haba, Hiromitsu*; Ichikawa, Takatoshi*; Ideguchi, Eiji*; Koura, Hiroyuki; Kudo, Yuki*; Ozawa, Akira*; Ozeki, Kazutaka*; et al.

no journal, , 

no abstracts in English

Oral presentation

Sub-barrier fusion hindrance in $$^{19}$$F+$$^{209}$$Bi reaction

Nishinaka, Ichiro; Kasamatsu, Yoshitaka*; Tanikawa, Masashi*; Goto, Shinichi*; Asai, Masato

no journal, , 

Unexpected steep falloff of fusion cross sections has recently been observed in heavy-ion fusion reactions at sub-barrier energies. In this work, the fusion-fission cross sections of 0.08-650 mb for $$^{19}$$F+$$^{209}$$Bi at incident beam energies of 83-135 MeV were determined by a radiochemical method in order to study sub-barrier fusion hindrance. We will discuss the sub-barrier fusion hindrance in the present reaction, comparing theoretical calculations and experimental data.

Oral presentation

Lateral distributions of Th-228 activity and Ra-228/Ra-226 activity ratio of surface water within the Sea of Japan, the East China Sea, and the Sea of Okhotsk

Yoshida, Keisuke*; Inoue, Mutsuo*; Minakawa, Masayuki*; Nakano, Yusuke*; Kofuji, Hisaki*; Otosaka, Shigeyoshi; Kiyomoto, Yoko*; Shiomoto, Akihiro*; Hamajima, Yasunori*; Yamamoto, Masayoshi*

no journal, , 

The authors have developed an analytical method for Th-228, Ra-226 and Ra-228 measurements in seawater using an ultra-low background $$gamma$$-ray detector. In this study, the authors measured the three radionuclides in surface seawater obtained from 16 stations in the Japan Sea, East China Sea and Okhotsk Sea. Concentrations of Ra-228 and Th-228 in surface waters in the southern Japan Sea were lower than those in the northern regions. Considering that the Th-228/Ra-228 activity ratios were not different between the northern and southern regions of the Japan Sea, we could conclude that (1) input of terrestrial materials from the East China Sea has not affected the distribution of the radionuclides in the Japan Sea, and (2) the efficiency of scavenging was not different between the regions.

Oral presentation

Status and perspectives of muon science at MUSE in J-PARC

Ninomiya, Kazuhiko

no journal, , 

no abstracts in English

Oral presentation

Production of long-lived Fm and Es tracers using a Cf target and its application to nuclear spectroscopy

Asai, Masato; Tsukada, Kazuaki; Kasamatsu, Yoshitaka*; Sato, Tetsuya; Toyoshima, Atsushi; Nagame, Yuichiro

no journal, , 

We have successfully obtained a large amount of long-lived Fm and Es tracers which can be used in various kinds of heavy-actinide chemistry experiments. Fm and Es isotopes were produced with a Cf target and a $$^{12}$$C beam from the JAEA tandem accelerator. Reaction products recoiling out of the target were collected with a gas-jet transport technique. After 3-day irradiation, Fm and Es isotopes were chemically separated from the collected products. By measuring $$alpha$$- and $$gamma$$-energy spectra, we evaluated an amount of each Fm and Es isotope, and other radioactive impurities. We also performed $$alpha$$-$$gamma$$ coincidence measurements for $$^{253}$$Fm using the same source.

Oral presentation

Study on dynamics and sources of POC in river systems using 14C as a tracer

Nagao, Seiya*; Aramaki, Takafumi*; Irino, Tomohisa*; Uchida, Masao*; Shibata, Yasuyuki*; Togawa, Orihiko

no journal, , 

no abstracts in English

37 (Records 1-20 displayed on this page)