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Journal Articles

Neutron transmission CB-KID imager using samples placed at room temperature

Ishida, Takekazu*; Vu, TheDang*; Shishido, Hiroaki*; Aizawa, Kazuya; Oku, Takayuki; Oikawa, Kenichi; Harada, Masahide; Kojima, Kenji M*; Miyajima, Shigeyuki*; Koyama, Tomio*; et al.

Journal of Low Temperature Physics, 214(3-4), p.152 - 157, 2024/02

JAEA Reports

Structural investigation of borosilicate glasses by using XAFS measurement in soft X-ray region, 3 (Joint research)

Nagai, Takayuki; Okamoto, Yoshihiro; Yamagishi, Hirona*; Shibata, Daisuke*; Kojima, Kazuo*; Hasegawa, Takehiko*; Sato, Seiichi*; Fukaya, Akane*; Hatakeyama, Kiyoshi*

JAEA-Research 2023-004, 45 Pages, 2023/09

JAEA-Research-2023-004.pdf:6.07MB

The local structure of glass-forming elements and waste elements in borosilicate glasses varies with its chemical composition. In this study, simulated waste glass samples were prepared and the chemical state regarding boron (B), silicon (Si) and waste elements of iron (Fe), cesium (Cs) were estimated by using XAFS measurement in soft X-ray region. To understand the chemical stability of simulated waste glasses, XANES spectra of B K-edge, Fe L$$_{3}$$, L$$_{2}$$-edge, and Cs M$$_{5}$$, M$$_{4}$$-edge were measured on the glass surface exposed to the leachate. As a result, it was found that the glass surface exposed to the leachate was changed and it was difficult to obtain a clear XANES spectrum. From the B K-edge XANES spectra on glass surfaces exposed to the leachate, an increase in three-coordination of B-O (BO$$_{3}$$) and a decrease in four-coordination of B-O (BO$$_{4}$$) were observed compared to the glass surfaces before immersion. The XANES spectra of Fe L$$_{3}$$, L$$_{2}$$-edge, and Cs M$$_{5}$$, M$$_{4}$$-edge show that as the exposure time in the leachate increases, the Cs present on the glass surface dissolves into the leachate. The XANES spectra of Si K-edge were measured on simulated waste glass surfaces before immersion, and it was confirmed that the change in XANES spectra given by Na$$_{2}$$O concentration had a larger effect than the waste component concentration.

Journal Articles

Orientation mapping of YbSn$$_{3}$$ single crystals based on Bragg-dip analysis using a delay-line superconducting sensor

Shishido, Hiroaki*; Vu, TheDang*; Aizawa, Kazuya; Kojima, Kenji M*; Koyama, Tomio*; Oikawa, Kenichi; Harada, Masahide; Oku, Takayuki; Soyama, Kazuhiko; Miyajima, Shigeyuki*; et al.

Journal of Applied Crystallography, 56(4), p.1108 - 1113, 2023/08

JAEA Reports

Structural investigation of borosilicate glasses by using XAFS measurement in soft X-ray region, 2 (Joint research)

Nagai, Takayuki; Okamoto, Yoshihiro; Yamagishi, Hirona*; Kojima, Kazuo*; Inose, Takehiko*; Sato, Seiichi*; Hatakeyama, Kiyoshi*

JAEA-Research 2022-008, 37 Pages, 2022/10

JAEA-Research-2022-008.pdf:5.27MB

The local structure of glass-forming elements and waste elements in borosilicate glasses varies with its chemical composition. In this study, borosilicate glass frit and simulated waste glass samples were prepared and the chemical state regarding boron (B), silicon (Si) and waste elements of iron (Fe), cesium (Cs) were estimated by using XAFS measurement in soft X-ray region. Following results were obtained by XAFS measurements of simulated waste glass surfaces after immersion test to investigate the long chemical stability. (1) As the leaching time of glass samples in immersion test passed, the Cs M$$_{5}$$, M$$_{4}$$-edge XANES spectra disappeared and the Fe L$$_{3}$$, L$$_{2}$$-edge spectra changed. (2) A new compound was formed on the sample surface after the immersion test, and these changes in the surface state were confirmed by Raman spectroscopy. However, it became difficult to obtain a clear B K-edge XANES spectrum by forming a compound on glass surfaces. The Si K-edge XANES spectra of borosilicate glass frits with different Na$$_{2}$$O content were measured, and following was confirmed. (1) As the Na$$_{2}$$O concentration increases in borosilicate glass frit, the K-edge peak of Si shifts to the low energy side. (2) The intensity of the Si K-edge peak is maximum when the Na$$_{2}$$O content in glass frits was about 7wt%.

JAEA Reports

Structural investigation of borosilicate glasses by using XAFS measurement in Soft X-ray region (Joint research)

Nagai, Takayuki; Okamoto, Yoshihiro; Yamagishi, Hirona*; Ota, Toshiaki*; Kojima, Kazuo*; Inose, Takehiko*; Sato, Seiichi*; Hatakeyama, Kiyoshi*

JAEA-Research 2021-010, 62 Pages, 2022/01

JAEA-Research-2021-010.pdf:6.05MB

The local structure of glass-forming elements and waste elements in borosilicate glasses varies with its chemical composition. In this study, borosilicate glass frit and simulated waste glass samples were prepared and the local structure and chemical state regarding boron(B), oxygen(O), silicon(Si) and waste elements of iron(Fe), cesium(Cs) were estimated by using XAFS measurement in soft X-ray region. Following results were obtained by XAFS measurements of prepared glass frit and simulated waste glass samples: (1) The effect of Na$$_{2}$$O concentration on B-O coordination structure is greater than that of the waste elements concentration. (2) The height of pre-edge by O K-edge spectrum depends on the concentration of first transition elements such as Fe in glass samples. Following results were obtained by XAFS measurements of simulated waste glass samples after immersion test to investigate the long chemical stability. (1) A new compound was formed on the sample surface after the immersion test, and changes in the surface state were confirmed by Raman spectroscopy. (2) Cs on the sample surface after immersion test dissolves into the leaching solution. The Si K-edge XANES spectra of borosilicate glass frits and simulated waste glass samples included lanthanides oxide were measured, and following was confirmed. (1) As the Na$$_{2}$$O concentration increases in borosilicate glass frit, the K-edge peak of Si shifts to the low energy side. (2) The peak height of the K-edge of Si differs depending on the kind of lanthanide.

Journal Articles

High spatial resolution neutron transmission imaging using a superconducting two-dimensional detector

Shishido, Hiroaki*; Nishimura, Kazuma*; Vu, TheDang*; Aizawa, Kazuya; Kojima, Kenji M*; Koyama, Tomio*; Oikawa, Kenichi; Harada, Masahide; Oku, Takayuki; Soyama, Kazuhiko; et al.

IEEE Transactions on Applied Superconductivity, 31(9), p.2400505_1 - 2400505_5, 2021/12

 Times Cited Count:0 Percentile:0(Engineering, Electrical & Electronic)

In this study, we employed a superconducting detector, current-biased kinetic-inductance detector (CB-KID) for neutron imaging using a pulsed neutron source. We employed the delay-line method, and high spatial resolution imaging with only four reading channels was achieved. We also performed wavelength-resolved neutron imaging by the time-of-flight method. We obtained the neutron transmission images of a Gd-Al alloy sample, inside which single crystals of GdAl$$_{3}$$ were grown, using the delay-line CB-KID. Single crystals were well imaged, in both shapes and distributions, throughout the Al-Gd alloy. We identified Gd nuclei via neutron transmissions that exhibited characteristic suppression above the neutron wavelength of 0.03 nm. In addition, the $$_{155}$$Gd resonance dip, a dip structure of the transmission caused by the nuclear reaction between an isotope and neutrons, was observed even when the number of events was summed over a limited area of 15 $$mu$$m $$times$$ 12 $$mu$$m. Gd selective imaging was performed using the resonance dip of $$_{155}$$Gd, and it showed clear Gd distribution even with a limited neutron wavelength range of 1 pm.

Journal Articles

Practical tests of neutron transmission imaging with a superconducting kinetic-inductance sensor

Vu, TheDang; Shishido, Hiroaki*; Aizawa, Kazuya; Kojima, Kenji M*; Koyama, Tomio*; Oikawa, Kenichi; Harada, Masahide; Oku, Takayuki; Soyama, Kazuhiko; Miyajima, Shigeyuki*; et al.

Nuclear Instruments and Methods in Physics Research A, 1006, p.165411_1 - 165411_8, 2021/08

 Times Cited Count:0 Percentile:0.02(Instruments & Instrumentation)

Journal Articles

Homogeneity of neutron transmission imaging over a large sensitive area with a four-channel superconducting detector

Vu, TheDang; Shishido, Hiroaki*; Kojima, Kenji M*; Koyama, Tomio*; Oikawa, Kenichi; Harada, Masahide; Miyajima, Shigeyuki*; Oku, Takayuki; Soyama, Kazuhiko; Aizawa, Kazuya; et al.

Superconductor Science and Technology, 34(1), p.015010_1 - 015010_10, 2021/01

 Times Cited Count:3 Percentile:28.82(Physics, Applied)

Journal Articles

Energy-resolved neutron imaging using a delay line current-biased kinetic-inductance detector

Shishido, Hiroaki*; Nishimura, Kazuma*; Vu, TheDang*; Kojima, Kenji M*; Koyama, Tomio*; Oikawa, Kenichi; Harada, Masahide; Miyajima, Shigeyuki*; Hidaka, Mutsuo*; Oku, Takayuki; et al.

Journal of Physics; Conference Series, 1590, p.012033_1 - 012033_8, 2020/10

JAEA Reports

Structural investigation of simulated waste glass samples by using XAFS measurement in soft X-ray region (Joint research)

Nagai, Takayuki; Okamoto, Yoshihiro; Yamagishi, Hirona*; Ota, Toshiaki*; Kojima, Kazuo*; Inose, Takehiko*; Sato, Seiichi*; Hatakeyama, Kiyoshi*

JAEA-Research 2020-009, 48 Pages, 2020/09

JAEA-Research-2020-009.pdf:4.53MB

The local structure of glass-forming elements and waste elements in waste glass varies with its chemical composition. In this study, borosilicate glass frit and simulated waste glass samples were prepared and the local structure and chemical state regarding boron (B), oxygen (O), and waste elements of cerium (Ce), cesium (Cs) were estimated by using XAFS measurement in soft X-ray region. Following results were obtained by XAFS measurements of prepared glass frit and simulated waste glass samples: (1) The existence ratio of four coordinate sp$$^{3}$$ structure (BO$$_{4}$$) tends to increase with increasing Na$$_{2}$$O content in glass samples. (2) The height of a pre-edge which appears by K-edge XANES spectrum of O is so high that the Fe content in glass samples. Following results were obtained by XAFS measurements of simulated waste glass samples after immersion test to investigate long chemical stability. (1) The existence ratio of four coordinate sp$$^{3}$$ structure (BO$$_{4}$$) increases by immersion test. (2) Ce which exists in the surface layer is oxidized by immersion test, and much of Cs in surface layer is lost after leach testing. Even if the glass frit form (fiber cartridge or beads) and manufacturing method were changed and a glass sample of the similar chemical composition was prepared, these observed Raman spectra of samples were different.

Journal Articles

Kinetic inductance neutron detector operated at near critical temperature

Vu, TheDang; Nishimura, Kazuma*; Shishido, Hiroaki*; Harada, Masahide; Oikawa, Kenichi; Miyajima, Shigeyuki*; Hidaka, Mutsuo*; Oku, Takayuki; Soyama, Kazuhiko; Aizawa, Kazuya; et al.

Journal of Physics; Conference Series, 1590, p.012036_1 - 012036_9, 2020/07

 Times Cited Count:0 Percentile:0.01

Journal Articles

Energy-resolved neutron imaging with high spatial resolution using a superconducting delay-line kinetic inductance detector

Iizawa, Yuki*; Shishido, Hiroaki*; Nishimura, Kazuma*; Vu, TheDang*; Kojima, Kenji M*; Koyama, Tomio*; Oikawa, Kenichi; Harada, Masahide; Miyajima, Shigeyuki*; Hidaka, Mutsuo*; et al.

Superconductor Science and Technology, 32(12), p.125009_1 - 125009_8, 2019/12

 Times Cited Count:11 Percentile:56.9(Physics, Applied)

Journal Articles

Temperature dependent characteristics of neutron signals from a current-biased Nb nanowire detector with $$^{10}$$B converter

Vu, TheDang; Iizawa, Yuki*; Nishimura, Kazuma*; Shishido, Hiroaki*; Kojima, Kenji*; Oikawa, Kenichi; Harada, Masahide; Miyajima, Shigeyuki*; Hidaka, Mutsuo*; Oku, Takayuki; et al.

Journal of Physics; Conference Series, 1293, p.012051_1 - 012051_9, 2019/10

 Times Cited Count:5 Percentile:93.54

Journal Articles

New precise measurements of muonium hyperfine structure at J-PARC MUSE

Strasser, P.*; Abe, Mitsushi*; Aoki, Masaharu*; Choi, S.*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; et al.

EPJ Web of Conferences, 198, p.00003_1 - 00003_8, 2019/01

 Times Cited Count:13 Percentile:99.28

Journal Articles

Excitation functions for production of Rf isotopes in the $$^{248}$$Cm + $$^{18}$$O reaction

Murakami, Masashi*; Goto, Shinichi*; Murayama, Hirofumi*; Kojima, Takayuki*; Kudo, Hisaaki*; Kaji, Daiya*; Morimoto, Koji*; Haba, Hiromitsu*; Kudo, Yuki*; Sumita, Takayuki*; et al.

Physical Review C, 88(2), p.024618_1 - 024618_8, 2013/08

 Times Cited Count:14 Percentile:66.75(Physics, Nuclear)

Production cross sections of Rf isotopes in the $$^{248}$$Cm + $$^{18}$$O reaction were measured at the beam energy range of 88.2 to 101.3 MeV by use of a gas-filled recoil ion separator. The excitation functions of $$^{260}$$Rf, $$^{261a}$$Rf, and $$^{262}$$Rf were obtained together with those of spontaneously fissioning nuclides which have few-second half-lives and have been assigned to $$^{261b}$$Rf and a longer-lived state of $$^{262}$$Rf. The excitation function of few-second spontaneously fissioning nuclide exhibited the maximum cross section at the $$^{18}$$O beam energy of 94.8 MeV. The shape of the excitation function was almost the same as that of $$^{261a}$$Rf, whereas it was quite different from those of $$^{260}$$Rf and $$^{262}$$Rf. A few-second spontaneously fissioning nuclide previously reported as $$^{261b}$$Rf and $$^{262}$$Rf observed in$$^{248}$$Cm + $$^{18}$$O reaction was identified as $$^{261b}$$Rf.

Journal Articles

Formation of NaCl-type monodeuteride LaD by the disproportionation reaction of LaD$$_{2}$$

Machida, Akihiko; Honda, Mitsunori*; Hattori, Takanori; Sano, Asami; Watanuki, Tetsu; Katayama, Yoshinori; Aoki, Katsutoshi; Komatsu, Kazuki*; Arima, Hiroshi*; Oshita, Hidetoshi*; et al.

Physical Review Letters, 108(20), p.205501_1 - 205501_5, 2012/05

 Times Cited Count:17 Percentile:67.51(Physics, Multidisciplinary)

Hydrogen atoms absorbed in a metal occupy the interstitial sites of the metal lattice. In an fcc metal lattice, each metal atom has two tetrahedral (T) and one octahedral (O) sites that can accommodate hydrogen. Rare-earth metal La forms T-site occupied LaH$$_2$$ and fully occupied LaH$$_3$$. O-site occupied or NaCl-type monohydride has yet to be reported for rare-earth metals. Previous X-ray diffraction measurements revealed the pressure-induced decomposition of an fcc-LaH$$_{2.3}$$ into H-rich and H-poor phases around 11 GPa. The present neutron diffraction measurements on LaD$$_{2}$$ confirm the formation of NaCl-type LaD as a counterpart of the D-rich LaD$$_{2+delta}$$ by disproportionation. First-principle calculations demonstrate that the NaCl-type LaH is stabilized at high pressures. Finding the NaCl-type LaH will pave the way for investigations on the site-dependent nature of hydrogen-metal interactions.

Journal Articles

Electronic structure of lithium amide

Kamakura, Nozomu; Takeda, Yukiharu; Saito, Yuji; Yamagami, Hiroshi; Tsubota, Masami*; Paik, B.*; Ichikawa, Takayuki*; Kojima, Yoshitsugu*; Muro, Takayuki*; Kato, Yukako*; et al.

Physical Review B, 83(3), p.033103_1 - 033103_4, 2011/01

 Times Cited Count:5 Percentile:25.44(Materials Science, Multidisciplinary)

The electronic structure of lithium amide, which is lightweight complex hydride expected as a high-capacity hydrogen storage material, is investigated by N 1$$s$$ soft X-ray emission spectroscopy (XES) and absorption spectroscopy (XAS). The overall feature of the electronic structure of lithium amide by the XES and XAS is consistent with the band calculation, while the strongly hybridized state with H 1$$s$$ is located at higher binding energy than the band calculation.

Journal Articles

Observation of ion cyclotron emission owing to DD fusion product H ions in JT-60U

Sato, Shoichi*; Ichimura, Makoto*; Yamaguchi, Yusuke*; Katano, Makoto*; Imai, Yasutaka*; Murakami, Tatsuya*; Miyake, Yuichiro*; Yokoyama, Takuro*; Moriyama, Shinichi; Kobayashi, Takayuki; et al.

Plasma and Fusion Research (Internet), 5, p.S2067_1 - S2067_4, 2010/12

Ion cyclotron emissions (ICEs) due to deuterium-deuterium fusion-product (FP) ions on JT-60U are studied. ICE due to H-ions is identified from the difference of the toroidal wave number of 2nd ICE(D). The parameter dependence for the appearance of ICE(H) is investigated from the experimental conditions and also is studied by using "Escape Particle Orbit analysis Code (EPOC)".

Journal Articles

Report of the 13th Young Scientist Workshop

Kojima, Atsushi; Kobayashi, Takayuki; Tobari, Hiroyuki

Purazuma, Kaku Yugo Gakkai-Shi, 86(5), P. 297, 2010/05

The 13th Young Scientist Workshop was held at Naka Fusion Institute and organized by Division of Advanced Plasma Research and Tokamak System Technology. 52 young scientists participated in the workshop, and 6 overview talks and 23 oral talks were given about plasma heating and control techniques. Because the participants had both of oral and poster presentations, the participants understood the study of each other and the discussion lasted during the workshop. On the last day of the workshop, the participants visited the ITER gyrotrons, ITER remote handling and the control room of JT-60.

Journal Articles

Progress of the IFMIF/EVEDA prototype accelerator in the Broader Approach activities for fusion energy in FY2008

Shinto, Katsuhiro; Vermare, C.*; Asahara, Hiroo; Sugimoto, Masayoshi; Garin, P.*; Maebara, Sunao; Takahashi, Hiroki; Sakaki, Hironao; Kojima, Toshiyuki; Ohira, Shigeru; et al.

Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.668 - 670, 2010/03

Progress of the IFMIF/EVEDA prototype accelerator in fiscal year of 2008 is described. All the sub-systems of the prototype accelerator have started to design, settled the plan of the manufacturing and component tests and fixed the design parameters. As a result of the analysis of planning for the engineering validation of the IFMIF accelerator system, the project duration to be prolonged to the end of 2014 including some months for contingency was approved by the BA Steering Committee. In this article, the design status of each accelerator component, the interface between the accelerator components and the IFMIF/EVEDA Accelerator Building settled in International Fusion Energy Research Centre (IFERC) in Rokkasho and the proposed accelerator commissioning plan for the engineering validation will be presented.

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