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Journal Articles

Two-step-pressurization method in pulsed electric current sintering of MoO$$_{3}$$ for production of $$^{99m}$$Tc radioactive isotope

Suematsu, Hisayuki*; Sato, Soma*; Nakayama, Tadachika*; Suzuki, Tatsuya*; Niihara, Koichi*; Nanko, Makoto*; Tsuchiya, Kunihiko

Journal of Asian Ceramic Societies (Internet), 8(4), p.1154 - 1161, 2020/12

 Times Cited Count:0 Percentile:100(Materials Science, Ceramics)

Pulsed electric current sintering of molybdenum trioxide (MoO$$_{3}$$) was carried out by one- and two-step pressuring methods for fabrication of irradiation target using production of $$^{99}$$Mo and $$^{rm 99m}$$Tc nuclear medicine. At 550$$^{circ}$$C by the two-step pressurizing method, a relative density of 93.1% was obtained while, by the one-step pressurization method, the relative density was 76.9%. Direct sample temperature measurements were conducted by inserting a thermocouple in a punch. By the two-step pressurizing method, the sample temperature was higher than that by the one-step pressurizing method even almost the same die temperature. From voltage and current waveforms, it was thought that the conductivity of the sample increased by the two-step pressurizing method to increase the sample temperature and the relative density. The two-step pressurization method enables us to prepare dense targets at a low temperature from recycled and coarse-grained $$^{98}$$Mo enriched MoO$$_{3}$$ powder.

Journal Articles

Suppression of decay widths in singly heavy baryons induced by the $$U_A(1)$$ anomaly

Kawakami, Yohei*; Harada, Masayasu*; Oka, Makoto; Suzuki, Kei

Physical Review D, 102(11), p.114004_1 - 114004_9, 2020/12

 Times Cited Count:0 Percentile:100(Astronomy & Astrophysics)

We study strong and radiative decays of excited singly heavy baryons using an effective chiral Lagrangian based on the diquark picture. The effective Lagrangian contains a $$U_A(1)$$ anomaly term, which is found to suppress the decay width of $$Lambda_Q(1/2^-) to Lambda_Q(1/2^+)eta$$.

Journal Articles

Spectrum of singly heavy baryons from a chiral effective theory of diquarks

Kim, Y.*; Hiyama, Emiko*; Oka, Makoto; Suzuki, Kei

Physical Review D, 102(1), p.014004_1 - 014004_9, 2020/07

 Times Cited Count:5 Percentile:7.64(Astronomy & Astrophysics)

Applying the chiral effective theory of diquarks, we analyze the spectrum and structure of singly heavy baryons. We introduce the phenomenological quark-model potentials for the confinement. We predict the charmed and bottom baryon spectrum showing the inverse mass hierarchy.

Journal Articles

Residual stress distribution in water jet peened type 304 stainless steel

Hayashi, Makoto*; Okido, Shinobu*; Suzuki, Hiroshi

Quantum Beam Science (Internet), 4(2), p.18_1 - 18_12, 2020/06

Journal Articles

Chiral effective theory of diquarks and the $$U_A(1)$$ anomaly

Harada, Masayasu*; Liu, Y.-R.*; Oka, Makoto; Suzuki, Kei

Physical Review D, 101(5), p.054038_1 - 054038_11, 2020/03

 Times Cited Count:5 Percentile:7.64(Astronomy & Astrophysics)

Using a chiral effective theory of diquarks, we analyze the spectrum and structure of diquark and heavy baryons consisting of diquarks. $$U_A(1)$$ anomaly is considered in the chiral Lagrangian and its effects are studied.

Journal Articles

Hadronic Paschen-Back effect in charmonium

Iwasaki, Sachio; Oka, Makoto; Suzuki, Kei*; Yoshida, Tetsuya*

AIP Conference Proceedings 2130, p.050001_1 - 050001_8, 2019/07

 Times Cited Count:0 Percentile:100

We find a novel phenomenon induced by the interplay between a strong magnetic field and finite orbital angular momenta in hadronic systems, which is analogous to the Paschen-Back effect observed in the field of atomic physics. This effect allows the wave functions to drastically deform. We discuss anisotropic decay from the deformation as a possibility to measure the strength of the magnetic field in heavy-ion collision at LHC, RHIC and SPS, which has not experimentally been measured. As an example we investigate charmonia with finite orbital angular momentum in a strong magnetic field. We calculate the mass spectra and mixing rate. To obtain anisotropic wave functions, we apply the cylindrical Gaussian expansion method, where the Gaussian bases to expand the wave functions have different widths along transverse and longitudinal directions in the cylindrical coordinate.

Journal Articles

Hadronic Paschen-Back effect in P-wave charmonia under strong magnetic fields

Iwasaki, Sachio; Oka, Makoto; Suzuki, Kei*; Yoshida, Tetsuya*

International Journal of Modern Physics; Conference Series (Internet), 49, p.1960002_1 - 1960002_6, 2019/07

The hadronic Paschen-Back effects in P-wave charmonia are analyzed using the constituent quark models in strong magnetic field.

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:99 Percentile:0.17(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

Hadronic Paschen-Back effect

Iwasaki, Sachio; Oka, Makoto; Suzuki, Kei*; Yoshida, Tetsuya*

Physics Letters B, 790, p.71 - 76, 2019/03

 Times Cited Count:4 Percentile:31.63(Astronomy & Astrophysics)

We find a novel phenomenon induced by the interplay between a strong magnetic field and finite orbital angular momenta in hadronic systems, which is analogous to the Paschen-Back effect observed in the field of atomic physics. This effect allows the wave functions to drastically deform. We discuss anisotropic decay from the deformation as a possibility to measure the strength of the magnetic field in heavy-ion collision at LHC, RHIC and SPS, which has not experimentally been measured. As an example we investigate charmonia with finite orbital angular momentum in a strong magnetic field. We calculate the mass spectra and mixing rate. To obtain anisotropic wave functions, we apply the cylindrical Gaussian expansion method, where the Gaussian bases to expand the wave functions have different widths along transverse and longitudinal directions in the cylindrical coordinate.

Journal Articles

Crack expansion and fracturing mode of hydraulic refracturing from Acoustic Emission monitoring in a small-scale field experiment

Ishida, Tsuyoshi*; Fujito, Wataru*; Yamashita, Hiroto*; Naoi, Makoto*; Fujii, Hirokazu*; Suzuki, Kenichiro*; Matsui, Hiroya

Rock Mechanics and Rock Engineering, 52(2), p.543 - 553, 2019/02

 Times Cited Count:2 Percentile:51.07(Engineering, Geological)

We pressurized and injected water in a hole drilled downward from a floor of the 500 m level gallery in MIU, central Japan. Acoustic emissions (AEs) monitored with 16 sensors in four boreholes located 1 m away from the HF hole exhibited two-dimensional distributions, which likely delineate a crack induced by the fracturing. Expansions of the regions in which AEs occurred were observed only immediately after the first and second BDs. Many AE events in other periods were distributed within the regions where AE events had already occurred. The initial motion polarities of P-waves indicate that tensile-dominant AE events occurred when the regions expanded and they were distributed primarily on the frontiers of the regions where AE events had already occurred. The experimental results suggest that increasing the injection flow rate is effective for generating new cracks in the refracturing, with the new crack expansions being induced by tensile fracturing.

Journal Articles

Charmonium ground and excited states at finite temperature from complex Borel sum rules

Araki, Kenji*; Suzuki, Kei*; Gubler, P.; Oka, Makoto

Physics Letters B, 780, p.48 - 53, 2018/05

 Times Cited Count:3 Percentile:50.83(Astronomy & Astrophysics)

Charmonium spectral functions in vector and pseudoscalar channels at finite temperature are investigated through the complex Borel sum rules and the maximum entropy method. Our approach enables us to extract the peaks corresponding to the excited charmonia, as well as those of the ground states, which has never been achieved in usual QCD sum rule analyses. We show the spectral functions in vacuum and their thermal modification around the critical temperature, which leads to the almost simultaneous melting (or peak disappearance) of the ground and excited states.

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:4 Percentile:71.42(Chemistry, Analytical)

no abstracts in English

Journal Articles

$$D$$ mesons in a magnetic field

Gubler, P.*; Hattori, Koichi*; Lee, S. H.*; Oka, Makoto; Ozaki, Sho*; Suzuki, Kei*

Physical Review D, 93(5), p.054026_1 - 054026_21, 2016/03

 Times Cited Count:35 Percentile:9.53(Astronomy & Astrophysics)

We investigate the mass spectra of open heavy flavor mesons in an external constant magnetic field within QCD sum rules. Spectral ansatze on the phenomenological side are proposed in order to properly take into account mixing effects between the pseudoscalar and vector channels, and the Landau levels of charged mesons. The operator product expansion is implemented up to dimension-5 operators. As a result, we find for neutral $$D$$ mesons a significant positive mass shift that goes beyond simple mixing effects. In contrast, charged $$D$$ mesons are further subject to Landau level effects, which together with the mixing effects almost completely saturate the mass shifts obtained in our sum rule analysis.

JAEA Reports

Proceedings of the 21st Meeting of the International Collaboration on Advanced Neutron Sources (ICANS-XXI); Sep. 29 - Oct.3, 2014, Ibaraki Prefectural Center, Mito, Japan

Oku, Takayuki; Nakamura, Mitsutaka; Sakai, Kenji; Teshigawara, Makoto; Hideki, Tatsumoto*; Yonemura, Masao*; Suzuki, Junichi*; Arai, Masatoshi*

JAEA-Conf 2015-002, 660 Pages, 2016/02

JAEA-Conf-2015-002.pdf:168.34MB

The twenty first meeting of the International Collaboration on Advanced Neutron Source (ICANS-XXI) was held at Ibaraki Prefectural Culture Center in Mito from 29 September to 3 October 2014. It was hosted by Japan Atomic Energy Agency (JAEA), High Energy Accelerator Research Organization (KEK) and Comprehensive Research Organization for Science and Society (CROSS). In the meeting, new science and technology in the new era with the high power neuron sources were discussed in mostly "workshop style" sessions. In each session, various kinds of issues related to not only the hardware, but also the software and even radiation safety were discussed with the keyword of "INTERFACE". More than 200 Papers were presented in the meeting and 72 contributed papers are compiled in the proceedings.

Journal Articles

R&D activities of tritium technologies on Broader Approach in Phase 2-2

Isobe, Kanetsugu; Kawamura, Yoshinori; Iwai, Yasunori; Oyaizu, Makoto; Nakamura, Hirofumi; Suzuki, Takumi; Yamada, Masayuki; Edao, Yuki; Kurata, Rie; Hayashi, Takumi; et al.

Fusion Engineering and Design, 98-99, p.1792 - 1795, 2015/10

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

Activities on Broader Approach (BA) were started in 2007 on the basis of the Agreement between the Government of Japan and the EURATOM. The period of BA activities consist of Phase1 and Phase2 dividing into Phase 2-1 (2010-2011), Phase 2-2 (2012-2013) and Phase 2-3 (2014-2016). Tritium technology was chosen as one of important R&D issues to develop DEMO plant. R&D activities of tritium technology on BA consist of four tasks. Task-1 is to prepare and maintain the tritium handling facility in Rokkasho BA site in Japan. Task 2, 3 and 4 are main R&D activities for tritium and these are focused on: Task-2) Development of tritium accountancy technology, Task-3) Development of basic tritium safety research, Task-4) Tritium durability test. R&D activities of tritium technology in Phase 2-2 were underway successfully and closed in 2013.

Journal Articles

Temperature of thermal spikes in amorphous silicon nitride films produced by 1.11 MeV C$$_{60}^{3+}$$ impacts

Kitayama, Takumi*; Nakajima, Kaoru*; Suzuki, Motofumi*; Narumi, Kazumasa; Saito, Yuichi; Matsuda, Makoto; Sataka, Masao*; Tsujimoto, Masahiko*; Isoda, Shoji*; Kimura, Kenji*

Nuclear Instruments and Methods in Physics Research B, 354, p.183 - 186, 2015/07

 Times Cited Count:2 Percentile:74.98(Instruments & Instrumentation)

Journal Articles

Recent progress on tritium technology research and development for a fusion reactor in Japan Atomic Energy Agency

Hayashi, Takumi; Nakamura, Hirofumi; Kawamura, Yoshinori; Iwai, Yasunori; Isobe, Kanetsugu; Yamada, Masayuki; Suzuki, Takumi; Kurata, Rie; Oyaizu, Makoto; Edao, Yuki; et al.

Fusion Science and Technology, 67(2), p.365 - 370, 2015/03

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

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

Biological significance of fluorine-18-$$alpha$$-methyltyrosine (FAMT) uptake on PET in patients with oesophageal cancer

Suzuki, Shigemasa*; Kaira, Kyoichi*; Ohshima, Yasuhiro; Ishioka, Noriko; Soda, Makoto*; Yokobori, Takehiko*; Miyazaki, Tatsuya*; Oriuchi, Noboru*; Tominaga, Hideyuki*; Kanai, Yoshikatsu*; et al.

British Journal of Cancer, 110(8), p.1985 - 1991, 2014/04

 Times Cited Count:18 Percentile:37.89(Oncology)

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:47 Percentile:2.85(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.

181 (Records 1-20 displayed on this page)