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6 results on '"Keiji Takahisa"'

2. Photoneutron reactions in nuclear astrophysics

Author

Therese Renstrøm, Hiroaki Utsunomiya, I. Gheorghe, Shuji Miyamoto, T. Shima, Keiji Takahisa, Stéphane Goriely, T. Glodariu, Yiu-Wing Lui, H. T. Nyhus, Ovidiu Tesileanu, and D. M. Filipescu

Subjects
Elastic scattering, Physics, History, Photon, Scattering, Physique, Astrophysics::High Energy Astrophysical Phenomena, Bremsstrahlung, Compton scattering, Synchrotron radiation, Electron, Astronomie, Computer Science Applications, Education, Nuclear physics, Nuclear astrophysics, Physics::Accelerator Physics
Abstract

Highly-monochromatic γ-ray beams are produced at the NewSUBARU synchrotron radiation facility by the inverse Compton scattering of laser photons from relativistic electrons. The latest s-process study in nuclear astrophysics with the γ-ray beam is presented., SCOPUS: cp.j, info:eu-repo/semantics/published

Published
2015

3. 3He Beam Development of 18 GHz SCECR-IS for Proton Generator at RCNP.

Author

Tetsuhiko Yorita, Keiji Takahisa, Mayuri Kobayashi, Ryusei Takaishi, Tatsushi Shima, Mitsuhiro Fukuda, Hiroki Kanda, and Yuusuke Yasuda

Subjects
*PARTICLE detectors, *CYCLOTRONS, *ELECTROSTATIC accelerators, *ION sources, *POLYETHYLENE, *NUCLEAR fusion
Abstract

Proton generator of several MeV for easy use like calibration of charged particle detector is needed instead of cyclotrons or electrostatic accelerators like Van de Graaff. So a proton generating system which consists of 18 GHz superconducting (SC)-ECR ion source and deuterated polyethylene target has been developed at the Research Center for Nuclear Physics (RCNP), Osaka University. The 3He2+ beam of 200eμA has been provided by SC-ECR ion source with 20 keV acceleration voltage and as a result of feasibility test of 3He+deuteron (D)→proton(P)+4He fusion reaction, the protons of 14.67 MeV have been obtained in 0.5Hz successfully. [ABSTRACT FROM AUTHOR]

Published
2018
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4. Titanium alloy as a potential low radioactivation vacuum material.

Author

Junichiro Kamiya, Yusuke Hikichi, Michikazu Kinsho, Norio Ogiwara, Mitsuhiro Fukuda, Noriaki Hamatani, Kichiji Hatanaka, Keita Kamakura, and Keiji Takahisa

Subjects
TITANIUM alloys, NUCLEAR activation analysis, VACUUM, PARTICLE accelerators, STRENGTH of materials, MICROFABRICATION
Abstract

For the vacuum systems of high-intensity beam accelerators, low radioactivation materials with good vacuum characteristics and high mechanical strength are required. The titanium alloy Ti-6Al-4V was investigated as a potential low activation vacuum material with high mechanical strength for the fabrication of vacuum components, particularly the flanges of beam pipes, in the J-PARC 3 GeV synchrotron. The dose rate of Ti-6Al-4V when irradiated by a 400 MeV proton was observed to decrease more rapidly than that of stainless steel. Furthermore, the generated radioactive isotopes were nuclides with relatively short half-lives. The outgassing rate per unit area of Ti-6Al-4V was approximately 10-8Pa m³/s m² after pumping for 100h, which is the same as the typical value for stainless steel. Additionally, the hydrogen concentration in bulk Ti-6Al-4V was reduced to approximately 1 ppm by vacuum firing at 700 °C for 9 h; the mechanical strength was not reduced by this process. These results indicate that Ti-6Al-4V is a good candidate for use as a low activation vacuum material with high mechanical strength. [ABSTRACT FROM AUTHOR]

Published
2015
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5. Limits on Majoron emitting neutrinoless double-beta decay of 100Mo

Author

H. Ohsumi, K. Matsuoka, Tadafumi Kishimoto, Ken-Ichi Fushimi, Nobuyuki Kudomi, Kyo Kume, Sei Yoshida, Keiji Takahisa, Hiroyasu Ejiri, K. Hayashi, and H. Kuramoto

Subjects
Nuclear physics, Physics, Coupling constant, Particle physics, Nuclear and High Energy Physics, Double beta decay, Half-life, Limit (mathematics), Lower limit, Majoron
Abstract

The single Majoron emitting neutrinoless double beta decay (0 νββB ) of 100 Mo was studied by means of ELEGANT V. A stringent lower limit on the half life was obtained as T 1/2 0 νββB >5.8(11)×10 21 yr at 90% (68%) C.L. The limit on the coupling constant |〈 g B 〉| was discussed in terms of the several nuclear models. The limit lies between 6.3×10 −5 and 3.6×10 −3 .

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6. Nuclear Reaction Dynamics Of Nucleon-hadron Many Body System: From Nucleon Spins And Mesons In Nuclei To Quark Lepton Nuclear Physics - Proceedings Of The 14th Rcnp Osaka International Symposium

Author

Hiroyasu Ejiri, Keiji Takahisa, Hiroshi Toki, Tetsuo Noro, Hiroyasu Ejiri, Keiji Takahisa, Hiroshi Toki, and Tetsuo Noro

Subjects
Nuclear reactions--Congresses, Hadron-nuclei interactions--Congresses, Many-body problem--Congresses
Abstract

The 14th RCNP OSAKA International Symposium on Nuclear Reaction Dynamics of Nucleon-Hadron Many Body System was held in Osaka from December 6 to 9, 1995. The symposium covered current topics from Nucleon Spins and Mesons in Nuclei to Quark Lepton Nuclear Physics. Thus it included the field of hadron/nuclear physics from sub-GeV to multi-GeV energy region, as well as recent activities and development at RCNP. It was also intended to be a kind of winter school for young researchers/graduate students.This proceedings consists of the invited talks and lectures presented by leading physicists in the field and short oral presentations.

Published
1996

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