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Journal Articles

Online solid-phase extraction-inductively coupled plasma-quadrupole mass spectrometric quantification of $$^{90}$$Sr using $$^{88}$$Sr/$$^{86}$$Sr isotope dilution method

Yanagisawa, Kayo*; Odashima, Mizuki*; Matsueda, Makoto; Furukawa, Makoto*; Takagai, Yoshitaka*

Talanta, 244, p.123442_1 - 123442_7, 2022/07

The determination of a low concentration of $$^{90}$$Sr was achieved by the combination of online SPE-ICP-QMS and ID method using $$^{88}$$Sr/$$^{86}$$Sr ratio. No requirement of radioactive standard material and the preparation process of the calibration curve was in the quantification process and data acquisition can be in one-shot sample injection. The proposed method allowed the rapid (within 15 min/sample) quantification of $$^{90}$$Sr in the presence of significant interferences such as isobaric $$^{90}$$Zr and other elements. The LOD for $$^{90}$$Sr was 5.6 Bq/L for a 10 mL injection and this could be improved by simply increasing the sample volume injected.

Journal Articles

Development of online dilution system for quantification of $$^{90}$$Sr using automatic solid-phase extraction inductively coupled plasma mass spectrometry

Yanagisawa, Kayo*; Matsueda, Makoto; Furukawa, Makoto*; Takagai, Yoshitaka*

Analytical Sciences, 36(9), p.1131 - 1135, 2020/09

 Times Cited Count:2 Percentile:41.67(Chemistry, Analytical)

In this paper, we propose an online water infusion system for rapid quantification of radioactive strontium-90 ($$^{90}$$Sr) with inductively coupled plasma mass spectrometry coupled solid-phase extraction and O$$_{2}$$ dynamic reaction (cascade ICP-MS). The proposed system automatically provides a higher dilution ratio, which is at most 3.3 times the ratio obtained by the previous method, without increasing the analysis time (within 15 min). A detection limit of 2.7 Bq/kg wet (0.54 pg/kg wet) was achieved. The recovery test results were consistent with two different spiked values.

Journal Articles

Experimental evaluation of wall shear stress in a double contraction nozzle using a water mock-up of a liquid Li target for an intense fusion neutron source

Kondo, Hiroo*; Kanemura, Takuji*; Park, C. H.*; Oyaizu, Makoto*; Hirakawa, Yasushi; Furukawa, Tomohiro

Fusion Engineering and Design, 146(Part A), p.285 - 288, 2019/09

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

Herein, the wall shear stress in a double contraction nozzle has been evaluated experimentally to produce a liquid lithium (Li) target as a beam target for intense fusion neutron sources such as the International Fusion Materials Irradiation Facility (IFMIF), the Advanced Fusion Neutron Source (A-FNS), and the DEMO Oriented Neutron Source (DONES). The boundary layer thickness and wall shear stress are essential physical parameters to understand erosion-corrosion by the high-speed liquid Li flow in the nozzle, which is the key component in producing a stable Li target. Therefore, these parameters were experimentally evaluated using an acrylic mock-up of the target assembly. The velocity distribution in the nozzle was measured by a laser-doppler velocimeter and the momentum thickness along the nozzle wall was calculated using an empirical prediction method. The resulting momentum thickness was used to estimate the variation of the wall shear stress along the nozzle wall. Consequently, the wall shear stress was at the maximum in the second convergent section in front of the nozzle exit.

Journal Articles

Radioactive strontium measurement using ICP-MS following cascade preconcentration and separation system

Takagai, Yoshitaka*; Furukawa, Makoto*; Kameo, Yutaka; Matsueda, Makoto; Suzuki, Katsuhiko*

Bunseki Kagaku, 66(4), p.223 - 231, 2017/04

 Times Cited Count:5 Percentile:28.23(Chemistry, Analytical)

no abstracts in English

Journal Articles

Rapid analysis of radioactive strontium by induction coupled plasma mass spectrometry

Takagai, Yoshitaka*; Furukawa, Makoto*; Kameo, Yutaka; Suzuki, Katsuhiko*

Isotope News, (721), p.2 - 7, 2014/05

no abstracts in English

Journal Articles

Sequential inductively coupled plasma quadrupole mass-spectrometric quantification of radioactive strontium-90 incorporating cascade separation steps for radioactive contamination rapid survey

Takagai, Yoshitaka*; Furukawa, Makoto*; Kameo, Yutaka; Suzuki, Katsuhiko*

Analytical Methods, 6(2), p.355 - 362, 2014/01

 Times Cited Count:52 Percentile:97.46(Chemistry, Analytical)

Radioactive strontium-90 ($$^{90}$$Sr) scattered by nuclear power plant accident was specifically determined by conventional inductively coupled plasma quadrupole mass-spectrometry (ICP-QMS) preceded by on-line chelate column separation and oxygen reaction. After implementing the cascade-step, the detection limit (DL) of quantitative ICP-QMS of $$^{90}$$Sr from spiked water samples was 2.85 Bq/L (equivalent to 0.56 ppq). Analysis of microwave-digested soil yielded a DL of 4.73 Bq/kg (equivalent to 0.93 ppq). The $$^{90}$$Sr from environmental contaminated soil samples ranged from 63 Bq/kg to 89 Bq/kg, with no statistical difference between the proposed and general methods at 98% confidence level.

Journal Articles

Isotope ratio analysis of $$^{235}$$U and $$^{238}$$U nuclide using a microwave digestion associated with ICP-MS and the large areal soil survey related to Fukushima Daiichi Nuclear Disaster

Takagai, Yoshitaka*; Furukawa, Makoto*; Nagahashi, Yoshitaka*; Takase, Tsugiko*; Shikino, Osamu*; Kameo, Yutaka

Bunseki Kagaku, 60(12), p.947 - 957, 2011/12

 Times Cited Count:12 Percentile:41.96(Chemistry, Analytical)

Isotope ratio analysis for $$^{235}$$U and $$^{238}$$U in soil samples using a microwave digestion procedure associated with ICP-MS was proposed and demonstrated. In the microwave digestion procedure, the dissolution of natural uranium in silicate (in rocks) was reduced by using a mixture of nitric acid and hydrogen peroxide (to measure the radioactive uranium from a disaster). Upon ICP-MS, the isotope ratio of the certificated geochemical reference material was realized to precisely correct the isotope ratio in real soil samples. In addition, cell-pass voltages can be available to make calibrations and/or to correct the mass bias in the mass-spectrometer. By these effects, the isotope ration of uranium can be measured with an accuracy of 0.37% without using a radioactive standard source. $$^{235}$$U and $$^{238}$$U were quantitatively determined, and those detection limits were both 0.010 $$mu$$g/kg. In the case of an emergency, like a nuclear hazard, the proposed method is useful to immediately gather a large amount of information in large area as compared with a common method such as a complete dissolution process associated with an $$alpha$$-ray spectrometer or ICP-MS. In addition, the survey of how radioactive uranium spreads was conducted from 7 to 80 km around the Fukushima Daiichi Nuclear Power Plant (Fukushima-DNPP) (115 points in Fukushima prefecture). As a result, the values of the uranium isotope ratio for those soils were similar to the natural abundance, although the various concentrations of uranium were detected from sampling points.

Journal Articles

Target system of IFMIF-EVEDA in Japanese activities

Ida, Mizuho; Fukada, Satoshi*; Furukawa, Tomohiro; Hirakawa, Yasushi; Horiike, Hiroshi*; Kanemura, Takuji*; Kondo, Hiroo; Miyashita, Makoto; Nakamura, Hiroo; Sugiura, Hirokazu*; et al.

Journal of Nuclear Materials, 417(1-3), p.1294 - 1298, 2011/10

 Times Cited Count:3 Percentile:28.8(Materials Science, Multidisciplinary)

Engineering Validation and Engineering Design Activities (EVEDA) of the International Fusion Materials Irradiation Facility (IFMIF) was started. As a Japanese activity for the target system, EVEDA Lithium Test Loop simulating hydraulic and impurity conditions of IFMIF is under design and preparation for fabrication. Feasibility of thermo-mechanical structure of the target assembly and the replaceable back-plate made of F82H (a RAFM) and 316L (a stainless steel) is a key issue. Toward final validation on the EVEDA loop, diagnostics applicable to a high-speed free-surface Li flow and hot traps to control nitrogen and hydrogen in Li are under tests. For remote handling of target assemblies and the replaceable back-plates activated up to 50 dpa/y, lip weld on 316L-316L by laser and dissimilar weld on F82H-316L are under investigation. As engineering design of the IFMIF target system, water experiments and hydraulic/thermo-mechanical analyses of the back-plate are going.

Journal Articles

Mechanisms of plasma rotation effects on the stability of type-I edge-localized mode in tokamaks

Aiba, Nobuyuki; Furukawa, Masaru*; Hirota, Makoto; Oyama, Naoyuki; Kojima, Atsushi; Tokuda, Shinji*; Yagi, Masatoshi

Nuclear Fusion, 51(7), p.073012_1 - 073012_9, 2011/07

We investigate numerically the destabilizing effect of a toroidal rotation on the edge localized MHD mode, which induces the large amplitude edge localized mode (ELM). As the results of this analysis, we reveal that the toroidal rotation with shear can destabilize this MHD mode, and the destabilization is caused by the difference between the plasma rotation frequency and the frequency of the unstable mode. Based on these results, we investigate numerically the stability of JT-60U type-I ELMy H-mode plasmas, and show that the toroidal rotation plays an important role for making the difference of ELM behavior observed in JT-60U plasmas with different plasma rotation profiles.

Journal Articles

Mechanisms of plasma rotation effects on the stability of type-I edge-localized mode in tokamaks

Aiba, Nobuyuki; Furukawa, Masaru*; Hirota, Makoto; Oyama, Naoyuki; Kojima, Atsushi; Tokuda, Shinji*; Yagi, Masatoshi

Nuclear Fusion, 51(7), p.073012_1 - 073012_9, 2011/07

 Times Cited Count:19 Percentile:67.23(Physics, Fluids & Plasmas)

Mechanisms of plasma rotation on edge MHD stability is investigated numerically by introducing energies that are distinguished by physics. By comparing them, it is found that an edge localized MHD mode is destabilized by the difference between an eigenmode frequency and an equilibrium toroidal rotation frequency, which is induced by rotation shear. In addition, this destabilizing effect becomes effective in the shorter wavelength region. The effect of poloidal rotation on the edge MHD stability is also investigated. Under the assumption that the change of an equilibrium by poloidal rotation is negligible, it is identified numerically that poloidal rotation can have both the stabilizing effect and the destabilizing effect on the edge MHD stability, which depends on the direction of poloidal rotation. Numerical analysis demonstrates that these effects of plasma rotation in both toroidal and poloidal directions can play important roles on type-I ELM phenomena in JT-60U H-mode plasmas.

Journal Articles

Engineering design and construction of IFMIF/EVEDA lithium test loop; Design and fabrication of integrated target assembly

Kondo, Hiroo; Furukawa, Tomohiro; Hirakawa, Yasushi; Nakamura, Hiroo*; Ida, Mizuho; Watanabe, Kazuyoshi; Miyashita, Makoto*; Horiike, Hiroshi*; Yamaoka, Nobuo*; Kanemura, Takuji; et al.

Proceedings of 23rd IAEA Fusion Energy Conference (FEC 2010) (CD-ROM), 8 Pages, 2010/10

The Engineering Validation and Engineering Design Activity (EVEDA) for the International Fusion Materials Irradiation Facility (IFMIF) is proceeded as one of the ITER Broader Approach (BA) activities. The EVEDA Li test loop (ELTL) is aimed at validating stability of the Li target and feasibility of a Li purification system as the key issues. In this paper, the design of the ELTL especially of a target assembly in which the Li target is produced by the contraction nozzle is presented.

Journal Articles

Recent progress in the energy recovery linac project in Japan

Sakanaka, Shogo*; Akemoto, Mitsuo*; Aoto, Tomohiro*; Arakawa, Dai*; Asaoka, Seiji*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2338 - 2340, 2010/05

Future synchrotron light source using a 5-GeV energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting R&D efforts for that. We are developing high-brightness DC photocathode guns, two types of cryomodules for both injector and main superconducting (SC) linacs, and 1.3 GHz high CW-power RF sources. We are also constructing the Compact ERL (cERL) for demonstrating the recirculation of low-emittance, high-current beams using above-mentioned critical technologies.

Journal Articles

Destabilization mechanism of edge localized MHD mode by a toroidal rotation in tokamaks

Aiba, Nobuyuki; Furukawa, Masaru*; Hirota, Makoto; Tokuda, Shinji

Nuclear Fusion, 50(4), p.045002_1 - 045002_13, 2010/04

 Times Cited Count:22 Percentile:68.5(Physics, Fluids & Plasmas)

In this paper, we investigate numerically the destabilizing effect of a toroidal rotation on the edge localized MHD mode, which induces the large amplitude edge localized mode (ELM). As the results of this analysis, we reveal that the toroidal rotation with shear can destabilize this MHD mode, and the destabilization is caused by the difference between the plasma rotation frequency and the frequency of the unstable mode, which mainly affects the pressure-driven component of the unstable mode. This destabilizing effect becomes more effective as the wave length of the mode becomes shorter, but such a MHD mode with short wave length is also stabilized by the sheared toroidal rotation due to the Doppler-shift at each flux surfaces. We clarify that the stability of the edge localized MHD mode, whose wave length is typically intermediate, is determined by the balance between these stabilizing and destabilizing effects.

Journal Articles

Progress in R&D efforts on the energy recovery linac in Japan

Sakanaka, Shogo*; Ago, Tomonori*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; Harada, Kentaro*; Hiramatsu, Shigenori*; Honda, Toru*; et al.

Proceedings of 11th European Particle Accelerator Conference (EPAC '08) (CD-ROM), p.205 - 207, 2008/06

Future synchrotron light sources based on the energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. Our Japanese collaboration team is making efforts for realizing an ERL-based hard X-ray source. We report recent progress in our R&D efforts.

Journal Articles

A New measurement of the astrophysical $$^8$$Li($$alpha$$, n)$$^{11}$$B reaction

Ishiyama, Hironobu*; Hashimoto, Takashi; Ishikawa, Tomoko*; Watanabe, Yutaka*; Das, S. K.*; Miyatake, Hiroari; Mizoi, Yutaka*; Fukuda, Tomokazu*; Tanaka, Masahiko*; Fuchi, Yoshihide*; et al.

Physics Letters B, 640(3), p.82 - 85, 2006/09

 Times Cited Count:31 Percentile:85.47(Astronomy & Astrophysics)

The excitation function of the $$^{8}$$Li($$alpha$$,n)$$^{11}$$B reaction was measured while identifying the final state event by event in the region of E$$_{rm{cm}}$$ = 0.7 - 2.6 MeV using a highly efficient detector system and a low-energy $$^8$$Li beam. The results are much improved both in statistics and precisions, and show smaller cross sections than those of previous measurements by a factor of more than 2 in the low-energy region of E$$_{rm{cm}}le$$ 1.5 MeV. A resonance-like structure is found at around E$$_{rm{cm}}$$ = 0.85 MeV.

Journal Articles

A New measurement of the $$^8$$Li($$alpha$$,n)$$^{11}$$B reaction for astrophysical interest

Das, S. K.*; Fukuda, Tomokazu*; Mizoi, Yutaka*; Ishiyama, Hironobu*; Miyatake, Hiroari*; Watanabe, Yutaka*; Hirayama, Yoshikazu*; Tanaka, Masahiko*; Yoshikawa, Nobuharu*; Jeong, S.-C.*; et al.

AIP Conference Proceedings 847, p.374 - 376, 2006/07

no abstracts in English

Journal Articles

Trouble of a transformer with the no-voltage tap changer

Omori, Yoshikazu; Kurihara, Kenichi; Matsukawa, Makoto; Terakado, Tsunehisa; Furukawa, Hiroshi

Dai-17-Kai Bunshi Kagaku Kenkyusho Gijutsu Kenkyukai Hokokushu (CD-ROM), 4 Pages, 2006/03

no abstracts in English

Journal Articles

Gated multiple-sampling and tracking proportional chamber; New detector system for nuclear astrophysical study with radioactive nuclear beams

Hashimoto, Takashi; Ishiyama, Hironobu*; Ishikawa, Tomoko*; Kawamura, Takashi*; Nakai, Koji*; Watanabe, Yutaka*; Miyatake, Hiroari; Tanaka, Masahiko*; Fuchi, Yoshihide*; Yoshikawa, Nobuharu*; et al.

Nuclear Instruments and Methods in Physics Research A, 556(1), p.339 - 349, 2006/01

 Times Cited Count:31 Percentile:89.78(Instruments & Instrumentation)

A new type of three dimensional tracking and proportional gas counter has been developed. Adopting a gating-grid system, performance of the detector becomes stable under the injection rate of charged particles less than 4$$times$$10$$^4$$ pps. It is a useful detection system for astrophysical experiments using radioactive nuclear beams, since the efficiency is so high as 100 %.

Journal Articles

A New intelligent coil current control system combined with a synchronous generator and a diode rectifier

Shimada, Katsuhiro; Omori, Yoshikazu; Furukawa, Hiroshi*; Terakado, Tsunehisa; Matsukawa, Makoto; Kurihara, Kenichi

Proceedings of International Conference on Electrical Engineering 2004 (ICEE 2004), p.777 - 781, 2004/00

We developed a new coil current control system for a power supply that consists of a synchronous generator and diode rectifiers. Test results are reported for the toroidal field coil power supply of JT-60, a world-class tokamak-type fusion device. This coil current control system has been designed to improve the control flexibility of the plasma discharge, and to introduce new functions. A state feedback control method is adopted to control coil current. Limit functions for the generator field current, the generator output voltage, and the toroidal field coil voltage have been added to the original coil current control system. Moreover, the abnormal state detection function of a coil is implemented for safety. The developed new intelligent control system has been tested and its performance was confirmed.

Journal Articles

Photofission of $$^{209}$$Bi at intermediate energies

Haba, Hiromitsu; Kasaoka, Makoto*; Igarashi, Manabu*; Washiyama, Koshin*; Matsumura, Hiroshi*; Oura, Yasuji*; Shibata, Seiichi*; Sakamoto, Ko*; Furukawa, Michiaki*; Fujiwara, Ichiro*

Radiochimica Acta, 90(7), p.371 - 382, 2002/08

 Times Cited Count:2 Percentile:17.59(Chemistry, Inorganic & Nuclear)

The reaction yields of 63 radionuclides with the mass number A = 56-135 produced in the photofission of $$^{209}$$Bi by bremsstrahlung of end-point energies (E$$_{0}$$) from 450 to 1100 MeV have been measured using a catcher foil technique. The charge distribution was well reproduced by a Gaussian function with the most probable charge (Z$$_{p}$$) expressed by Z$$_{p}$$ = RA + S, and with the A-independent FWHME$$_{CD}$$. The charge distribution parameters R, S and FWHM$$_{CD}$$ were independent of E$$_{0}$$ above 600 MeV. The weighted mean values at E$$_{0}$$ $$geq$$ 600 MeV were R = 0.421 $$pm$$ 0.001, S = 0.6 $$pm$$ 0.1 and FWHM$$_{CD}$$ = 2.1 $$pm$$ 0.1 charge unit (c.u.). Based on the charge distribution parameters, the symmetric mass yield distributions with the most probable mass A$$_{p}$$ of 96 $$pm$$ 1 mass unit (m.u.) and the width FWHM$$_{MD}$$ of 33 $$pm$$ 1 m.u. were also obtained. The characteristics of the charge and mass yield distributions are discussed by referring to those for $$^{197}$$Au based on the results of calculations using PICA3/GEM.

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