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Journal Articles

Competition between mass-symmetric and asymmetric fission modes in $$^{258}$$Md produced in the $$^{4}$$He + $$^{254}$$Es reaction

Nishio, Katsuhisa; Hirose, Kentaro; Makii, Hiroyuki; Orlandi, R.; Kean, K. R.*; Tsukada, Kazuaki; Toyoshima, Atsushi*; Asai, Masato; Sato, Tetsuya; Chiera, N. M.*; et al.

Physical Review C, 111(4), p.044609_1 - 044609_12, 2025/04

 Times Cited Count:0

Journal Articles

Effect of carbon segregation at prior austenite grain boundary on hydrogen-related crack propagation behavior in 3Mn-0.2C martensitic steels

Okada, Kazuho*; Shibata, Akinobu*; Kimura, Yuji*; Yamaguchi, Masatake; Ebihara, Kenichi; Tsuji, Nobuhiro*

Acta Materialia, 280, p.120288_1 - 120288_14, 2024/11

 Times Cited Count:1 Percentile:0.00(Materials Science, Multidisciplinary)

Journal Articles

Current numbers of qubits and their uses

Ichikawa, Tsubasa*; Hakoshima, Hideaki*; Inui, Koji*; Ito, Kosuke*; Matsuda, Ryo*; Mitarai, Kosuke*; Miyamoto, Koichi*; Mizukami, Wataru*; Mizuta, Kaoru*; Mori, Toshio*; et al.

Nature Reviews Physics (Internet), 6(6), p.345 - 347, 2024/06

 Times Cited Count:7 Percentile:99.15(Physics, Applied)

Journal Articles

Benchmark analysis by Beremin model and GTN model in CAF Subcommittee

Nagoshi, Yasuto*; Fukahori, Takuya*; Okada, Hiroshi*; Takahashi, Akiyuki*; Shimodaira, Masaki; Ueda, Takashi*; Ogawa, Takuya*; Yashirodai, Kenji*; Takahashi, Yukio*; Ohata, Mitsuru*

Transactions of the 27th International Conference on Structural Mechanics in Reactor Technology (SMiRT 27) (Internet), 9 Pages, 2024/03

no abstracts in English

Journal Articles

Microstructural evolution of intermetallic phase precipitates in Cr-coated zirconium alloy cladding in high-temperature steam oxidation up to 1400$$^{circ}$$C

Mohamad, A. B.; Nemoto, Yoshiyuki; Furumoto, Kenichiro*; Okada, Yuji*; Sato, Daiki*

Corrosion Science, 224, p.111540_1 - 111540_15, 2023/11

 Times Cited Count:5 Percentile:55.06(Materials Science, Multidisciplinary)

Journal Articles

Survey on technical issues of fission products behavior for improvement of decommissioning work efficiency and source term predicting accuracy; Report on the activity of this research committee for 2 years

Katsumura, Kosuke*; Takagi, Junichi*; Hosomi, Kenji*; Miyahara, Naoya*; Koma, Yoshikazu; Imoto, Jumpei; Karasawa, Hidetoshi; Miwa, Shuhei; Shiotsu, Hiroyuki; Hidaka, Akihide*; et al.

Nihon Genshiryoku Gakkai-Shi ATOMO$$Sigma$$, 65(11), p.674 - 679, 2023/11

no abstracts in English

Journal Articles

Role of resonance states of muonic molecule in muon catalyzed fusion

Okutsu, Kenichi*; Yamashita, Takuma*; Kino, Yasushi*; Miyashita, Konan*; Yasuda, Kazuhiro*; Oka, Toshitaka; Okada, Shinji*; Sato, Motoyasu*

JJAP Conference Proceedings (Internet), 9, p.011003_1 - 011003_7, 2023/00

Muon catalyzed fusion ($$mu$$CF) is a cyclic reaction where a negatively charged muon itself acts like a catalyst of nuclear fusion between hydrogen isotopes. In the $$mu$$CF reaction, muon transfer from deuteron to triton and muonic molecular formation are rate-limiting processes. In this work, we have investigated the role of resonance states of muonic molecule in the $$mu$$CF which affects the muonic deuterium atom population. Solving simultaneous rate equations numerically by the fourth-order Runge-Kutta method, we determined the muonic molecular formation rate so that the number of fusion events reproduces a latest experimental result. It is revealed that the resonance states play a role to enhance the fusion rate by accelerating the de-excitation of the muonic atoms.

Journal Articles

Design for detecting recycling muon after muon-catalyzed fusion reaction in solid hydrogen isotope target

Okutsu, Kenichi*; Yamashita, Takuma*; Kino, Yasushi*; Nakashima, Ryota*; Miyashita, Konan*; Yasuda, Kazuhiro*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.

Fusion Engineering and Design, 170, p.112712_1 - 112712_4, 2021/09

 Times Cited Count:3 Percentile:31.52(Nuclear Science & Technology)

A muonic molecule which consists of two hydrogen isotope nuclei (deuteron (d) or tritium (t)) and a muon decays immediately via nuclear fusion and the muon will be released as a recycling muon, and start to find another hydrogen isotope nucleus. The reaction cycle continues until the muon ends up its lifetime of 2.2 $$mu$$s. Since the muon does not participate in the nuclear reaction, the reaction is so called a muon catalyzed fusion ($$mu$$CF). The recycling muon has a particular kinetic energy (KE) of the muon molecular orbital when the nuclear reaction occurs. Since the KE is based on the unified atom limit where distance between two nuclei is zero. A precise few-body calculation estimating KE distribution (KED) is also in progress, which could be compared with the experimental results. In the present work, we observed recycling muons after $$mu$$CF reaction.

Journal Articles

Time evolution calculation of muon catalysed fusion; Emission of recycling muons from a two-layer hydrogen film

Yamashita, Takuma*; Okutsu, Kenichi*; Kino, Yasushi*; Nakashima, Ryota*; Miyashita, Konan*; Yasuda, Kazuhiro*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.

Fusion Engineering and Design, 169, p.112580_1 - 112580_5, 2021/08

 Times Cited Count:3 Percentile:31.52(Nuclear Science & Technology)

A muon ($$mu$$) having 207 times larger mass of electron and the same charge as the electron has been known to catalyze a nuclear fusion between deuteron (d) and triton (t). These two nuclei are bound by $$mu$$ and form a muonic hydrogen molecular ion, dt$$mu$$. Due to the short inter-nuclear distance of dt$$mu$$, the nuclear fusion, d +t$$rightarrow alpha$$ + n + 17.6 MeV, occurs inside the molecule. This reaction is called muon catalyzed fusion ($$mu$$CF). Recently, the interest on $$mu$$CF is renewed from the viewpoint of applications, such as a source of high-resolution muon beam and mono-energetic neutron beam. In this work, we report a time evolution calculation of $$mu$$CF in a two-layered hydrogen isotope target.

Journal Articles

Dynamical response of transition-edge sensor microcalorimeters to a pulsed charged-particle beam

Okumura, Takuma*; Azuma, Toshiyuki*; Bennet, D. A.*; Caradonna, P.*; Chiu, I.-H.*; Doriese, W. B.*; Durkin, M. S.*; Fowler, J. W.*; Gard, J. D.*; Hashimoto, Tadashi; et al.

IEEE Transactions on Applied Superconductivity, 31(5), p.2101704_1 - 2101704_4, 2021/08

 Times Cited Count:2 Percentile:14.18(Engineering, Electrical & Electronic)

A superconducting transition-edge sensor (TES) microcalorimeter is an ideal X-ray detector for experiments at accelerator facilities because of good energy resolution and high efficiency. To study the performance of the TES detector with a high-intensity pulsed charged-particle beam, we measured X-ray spectra with a pulsed muon beam at the Japan Proton Accelerator Research Complex (J-PARC) in Japan. We found substantial temporal shifts of the X-ray energy correlated with the arrival time of the pulsed muon beam, which was reasonably explained by pulse pileup due to the incidence of energetic particles from the initial pulsed beam.

Journal Articles

Deexcitation dynamics of muonic atoms revealed by high-precision spectroscopy of electronic $$K$$ X rays

Okumura, Takuma*; Azuma, Toshiyuki*; Bennet, D. A.*; Caradonna, P.*; Chiu, I. H.*; Doriese, W. B.*; Durkin, M. S.*; Fowler, J. W.*; Gard, J. D.*; Hashimoto, Tadashi; et al.

Physical Review Letters, 127(5), p.053001_1 - 053001_7, 2021/07

 Times Cited Count:17 Percentile:76.61(Physics, Multidisciplinary)

We observed electronic $$K$$X rays emitted from muonic iron atoms using a superconducting transition-edge-type sensor microcalorimeter. The energy resolution of 5.2 eV in FWHM allowed us to observe the asymmetric broad profile of the electronic characteristic $$K$$$$alpha$$ and $$K$$$$beta$$ X rays together with the hypersatellite $$K$$$$alpha$$ X rays around 6 keV. This signature reflects the time-dependent screening of the nuclear charge by the negative muon and the $$L$$-shell electrons, accompanied by electron side-feeding. Assisted by a simulation, this data clearly reveals the electronic $$K$$- and $$L$$-shell hole production and their temporal evolution during the muon cascade process.

Journal Articles

Benchmark analysis by Beremin model and GTN model in CAF subcommittee

Hirota, Takatoshi*; Nagoshi, Yasuto*; Hojo, Kiminobu*; Okada, Hiroshi*; Takahashi, Akiyuki*; Katsuyama, Jinya; Ueda, Takashi*; Ogawa, Takuya*; Yashirodai, Kenji*; Ohata, Mitsuru*; et al.

Proceedings of ASME 2021 Pressure Vessels and Piping Conference (PVP 2021) (Internet), 9 Pages, 2021/07

Journal Articles

Thermally altered subsurface material of asteroid (162173) Ryugu

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.

Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03

 Times Cited Count:58 Percentile:96.23(Astronomy & Astrophysics)

Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 $$^{circ}$$C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 $$^{circ}$$C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.

Journal Articles

$$q$$=0 long-range magnetic order in centennialite CaCu$$_{3}$$(OD)$$_{6}$$Cl$$_{2}$$ $$cdot$$ 0.6D$$_{2}$$O; A Spin-$$frac{1}{2}$$ perfect kagome antiferromagnet with $$J_{1}$$-$$J_{2}$$-$$J_{d}$$

Iida, Kazuki*; Yoshida, Hiroyuki*; Nakao, Akiko*; Jeschke, H. O.*; Iqbal, Y.*; Nakajima, Kenji; Kawamura, Seiko; Munakata, Koji*; Inamura, Yasuhiro; Murai, Naoki; et al.

Physical Review B, 101(22), p.220408_1 - 220408_6, 2020/06

 Times Cited Count:28 Percentile:79.33(Materials Science, Multidisciplinary)

Crystal and magnetic structures of the mineral centennialite CaCu$$_{3}$$(OD)$$_{6}$$Cl$$_{2}$$ $$cdot$$ 0.6D$$_{2}$$O are investigated by means of synchrotron X-ray diffraction and neutron diffraction measurements complemented by density functional theory (DFT) and pseudofermion functional renormalization group (PFFRG) calculations. In CaCu$$_{3}$$(OD)$$_{6}$$Cl$$_{2}$$ $$cdot$$ 0.6D$$_{2}$$O, Cu$$^{2+}$$ ions form a geometrically perfect kagome network with antiferromagnetic $$J_{1}$$. No intersite disorder between Cu$$^{2+}$$ and Ca$$^{2+}$$ ions is detected. CaCu$$_{3}$$(OD)$$_{6}$$Cl$$_{2}$$ $$cdot$$ 0.6D$$_{2}$$O enters a magnetic long-range ordered state below $$T_{rm N}$$ = 7.2 K, and the $$q$$=0 magnetic structure with negative vector spin chirality is obtained. The ordered moment at 0.3 K is suppressed to 0.58(2)$$mu$$B. Our DFT calculations indicate the presence of antiferromagnetic $$J_{2}$$ and ferromagnetic $$J_{d}$$ superexchange couplings of a strength which places the system at the crossroads of three magnetic orders (at the classical level) and a spin-$$frac{1}{2}$$ PFFRG analysis shows a dominance of $$q$$=0 type magnetic correlations, consistent with and indicating proximity to the observed $$q$$=0 spin structure. The results suggest that this material is located close to a quantum critical point and is a good realization of a $$J_{1}$$-$$J_{2}$$-$$J_{d}$$ kagome antiferromagnet.

Journal Articles

$$omega N$$ scattering length from $$omega$$ photoproduction on the proton near the reaction threshold

Ishikawa, Takatsugu*; Fujimura, Hisako*; Fukasawa, Hiroshi*; Hashimoto, Ryo*; He, Q.*; Honda, Yuki*; Hosaka, Atsushi; Iwata, Takahiro*; Kaida, Shun*; Kasagi, Jirota*; et al.

Physical Review C, 101(5), p.052201_1 - 052201_6, 2020/05

 Times Cited Count:4 Percentile:37.19(Physics, Nuclear)

Journal Articles

A New approach for measuring the muon anomalous magnetic moment and electric dipole moment

Abe, Mitsushi*; Bae, S.*; Beer, G.*; Bunce, G.*; Choi, H.*; Choi, S.*; Chung, M.*; da Silva, W.*; Eidelman, S.*; Finger, M.*; et al.

Progress of Theoretical and Experimental Physics (Internet), 2019(5), p.053C02_1 - 053C02_22, 2019/05

 Times Cited Count:156 Percentile:99.31(Physics, Multidisciplinary)

This paper introduces a new approach to measure the muon magnetic moment anomaly $$a_{mu}=(g-2)/2$$ and the muon electric dipole moment (EDM) $$d_{mu}$$ at the J-PARC muon facility. The goal of our experiment is to measure $$a_{mu}$$ and $$d_{mu}$$ using an independent method with a factor of 10 lower muon momentum, and a factor of 20 smaller diameter storage-ring solenoid compared with previous and ongoing muon g-2 experiments with unprecedented quality of the storage magnetic field. Additional significant differences from the present experimental method include a factor of 1000 smaller transverse emittance of the muon beam (reaccelerated thermal muon beam), its efficient vertical injection into the solenoid, and tracking each decay positron from muon decay to obtain its momentum vector. The precision goal for $$a_{mu}$$ is a statistical uncertainty of 450 parts per billion (ppb), similar to the present experimental uncertainty, and a systematic uncertainty less than 70 ppb. The goal for EDM is a sensitivity of $$1.5times10^{-21}$$ e$$cdot$$cm.

Journal Articles

The Surface composition of asteroid 162173 Ryugu from Hayabusa2 near-infrared spectroscopy

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Arai, Takehiko*; Nakauchi, Yusuke*; Nakamura, Tomoki*; Matsuoka, Moe*; et al.

Science, 364(6437), p.272 - 275, 2019/04

 Times Cited Count:298 Percentile:99.68(Multidisciplinary Sciences)

The near-Earth asteroid 162173 Ryugu, the target of Hayabusa2 sample return mission, is believed to be a primitive carbonaceous object. The Near Infrared Spectrometer (NIRS3) on Hayabusa2 acquired reflectance spectra of Ryugu's surface to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micron was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally- and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.

Journal Articles

Angular distribution of $$gamma$$ rays from neutron-induced compound states of $$^{140}$$La

Okudaira, Takuya*; Takada, Shusuke*; Hirota, Katsuya*; Kimura, Atsushi; Kitaguchi, Masaaki*; Koga, Jun*; Nagamoto, Kosuke*; Nakao, Taro*; Okada, Anju*; Sakai, Kenji; et al.

Physical Review C, 97(3), p.034622_1 - 034622_15, 2018/03

 Times Cited Count:18 Percentile:78.26(Physics, Nuclear)

JAEA Reports

XAFS measurement of simulated waste glass samples (Borosilicate glass including vanadium)

Nagai, Takayuki; Kobayashi, Hidekazu; Sasage, Kenichi; Ayame, Yasuo; Okamoto, Yoshihiro; Shiwaku, Hideaki; Matsuura, Haruaki*; Uchiyama, Takafumi*; Okada, Yukiko*; Nezu, Atsushi*; et al.

JAEA-Research 2016-015, 52 Pages, 2016/11

JAEA-Research-2016-015.pdf:37.48MB

The local structure of waste elements in simulated waste glasses including V was estimated by using synchrotron XAFS measurement in this study. The results are as follows. (1) V has a high possibility which exists in the glass phase in the case of frit, and V can regard both samples as stable 4 coordination structure. (2) Zn, Ce, Nd, Zr, and Mo exist in the glass phase, and the difference is admitted by the percentage of Ce(III) and Ce(IV) by the composition. (3) Ru is separated from the glass phase as RuO$$_{2}$$ crystalline, both of metal and oxide exist in Rh, and Pd is separated out as metal. (4) It was confirmed that the regularity of the local structure of Zr and Mo in the molten glasses retreats as a result of the XAFS measurement at high temperature. (5) The XAFS measurement of molten glasses were performed at 1200$$^{circ}$$C, so it would be possible to acquire excellent data by improving the shapes of the sample cell.

JAEA Reports

Performance confirmation operation of water environment control facility

Magome, Hirokatsu; Okada, Yuji; Tomita, Kenji; Iida, Kazuhiro; Ando, Hitoshi; Yonekawa, Akihisa; Ueda, Haruyasu; Hanawa, Hiroshi; Kanno, Masaru; Sakuta, Yoshiyuki

JAEA-Technology 2015-025, 100 Pages, 2015/09

JAEA-Technology-2015-025.pdf:78.32MB

In Japan Atomic Energy Agency, in order to solve the problem in the long-term operation of a light water reactor, preparation which does the irradiation experiment of light-water reactor fuel and material was advanced. JMTR stopped after the 165th operation cycle in August 2006, and is advancing renewal of the irradiation facility towards re-operation. The material irradiation test facility was installed from 2008 fiscal year to 2012 fiscal year in JMTR. The material irradiation test facility is used for IASCC study, and that consists of mainly three equipments. This report is described performance operating test of the water environmental control facilities for IASCC study carried out 2013 fiscal year.

132 (Records 1-20 displayed on this page)