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Journal Articles

Enhancement of element production by incomplete fusion reaction with weakly bound deuteron

Wang, H.*; Otsu, Hideaki*; Chiga, Nobuyuki*; Kawase, Shoichiro*; Takeuchi, Satoshi*; Sumikama, Toshiyuki*; Koyama, Shumpei*; Sakurai, Hiroyoshi*; Watanabe, Yukinobu*; Nakayama, Shinsuke; et al.

Communications Physics (Internet), 2(1), p.78_1 - 78_6, 2019/07

 Times Cited Count:8 Percentile:56.2(Physics, Multidisciplinary)

Searching for effective pathways for the production of proton- and neutron-rich isotopes through an optimal combination of reaction mechanism and energy is one of the main driving forces behind experimental and theoretical nuclear reaction studies as well as for practical applications in nuclear transmutation of radioactive waste. We report on a study on incomplete fusion induced by deuteron, which contains one proton and one neutron with a weak binding energy and is easily broken up. This reaction study was achieved by measuring directly the cross sections for both proton and deuteron for $$^{107}$$Pd at 50 MeV/u via inverse kinematics technique. The results provide direct experimental evidence for the onset of a cross-section enhancement at high energy, indicating the potential of incomplete fusion induced by loosely-bound nuclei for creating proton-rich isotopes and nuclear transmutation of radioactive waste.

Journal Articles

Contracted interlayer distance in graphene/sapphire heterostructure

Entani, Shiro; Antipina, L. Y.*; Avramov, P.*; Otomo, Manabu*; Matsumoto, Yoshihiro*; Hirao, Norie; Shimoyama, Iwao; Naramoto, Hiroshi*; Baba, Yuji; Sorokin, P. B.*; et al.

Nano Research, 8(5), p.1535 - 1545, 2015/05

 Times Cited Count:26 Percentile:71.65(Chemistry, Physical)

Journal Articles

Evidence for a new nuclear "magic number" from the level structure of $$^{54}$$Ca

Steppenbeck, D.*; Takeuchi, Satoshi*; Aoi, Nori*; Doornenbal, P.*; Matsushita, Masafumi*; Wang, H.*; Baba, Hidetada*; Fukuda, Naoki*; Go, Shintaro*; Homma, Michio*; et al.

Nature, 502(7470), p.207 - 210, 2013/10

 Times Cited Count:285 Percentile:99.78(Multidisciplinary Sciences)

no abstracts in English

Journal Articles

Response functions of Phoswich-type neutron detector for high-energy cosmic ray neutron measurement

Takada, Masashi*; Yajima, Kazuaki*; Yasuda, Hiroshi*; Nakamura, Takashi*; Baba, Mamoru*; Homma, Toshihiro*; Endo, Akira; Tanimura, Yoshihiko

Journal of Nuclear Science and Technology, 47(10), p.917 - 931, 2010/10

 Times Cited Count:6 Percentile:40.28(Nuclear Science & Technology)

A phoswich-type neutron detector was developed in order to measure high-energy cosmic-ray neutron spectrum in aircrafts. The neutron detector consists of a 121.7 mm diameter and a 121.7 mm long EJ309 organic liquid scintillator covered with a 15 mm thick EJ299-13 outer plastic scintillator. Neutron response functions of the detector are required for an unfolding method to get the energy spectrum. The neutron response functions were evaluated from measurements using quasi-monoenergetic neutron sources of various peak energies from 35 to 78 MeV and from the MCNPX simulation. Light output and scintillation attenuation in the scintillator were measured for proton, deuteron and helium-ion beams. The measured neutron response functions well agreed with the MCNPX simulation. Neutron response matrix was created up to 300 MeV neutron energy based on the MCNPX simulation in order to cover the wide neutron energy range in the fight experiment. Photon response matrix also was created up to 50 MeV.

Journal Articles

Vacuum brazing of the new RFQ for the J-PARC linac

Morishita, Takatoshi; Kondo, Yasuhiro; Hasegawa, Kazuo; Naito, Fujio*; Yoshioka, Masakazu*; Matsumoto, Hiroshi*; Hori, Yoichiro*; Kawamata, Hiroshi*; Saito, Yoshio*; Baba, Hiroshi*

Proceedings of 25th International Linear Accelerator Conference (LINAC 2010) (CD-ROM), p.521 - 523, 2010/09

The fabrication of a new RFQ has been started as a backup machine for the J-PARC linac. The RFQ cavity is divided by three unit tanks in the longitudinal direction. The unit tank consists of two major vanes and two minor vanes, those are brazed together. A one-step vacuum brazing of a unit tank was adopted to unite these four vanes together with the flanges and ports. At the first tank brazing, the vacuum leak has been occurred due to the non-uniform temperature rise during the heating. Repair of this leakage and the results of the improved brazing of the second tank are reported.

Journal Articles

Vane machining by the ball-end-mill for the new RFQ in the J-PARC linac

Morishita, Takatoshi; Kondo, Yasuhiro; Hasegawa, Kazuo; Kawamata, Hiroshi*; Naito, Fujio*; Yoshioka, Masakazu*; Matsumoto, Hiroshi*; Hori, Yoichiro*; Saito, Yoshio*; Baba, Hiroshi*

Proceedings of 25th International Linear Accelerator Conference (LINAC 2010) (CD-ROM), p.518 - 520, 2010/09

The fabrication of a new RFQ has been started in the J-PARC linac. The RFQ cavity is divided by three unit tanks in the longitudinal direction. The unit tank consists of two major vanes and two minor vanes, those will be brazed together. To reduce the costs and periods to develop the special formed bite for the modulation machining, a numerical controlled machining using a conventional ball-end-mill was adopted for the vane modulation cutting instead of the wheel shape cutter. The dimension accuracy was confirmed by cutting test pieces. Moreover, the obtained surface seems smooth enough for the operation. Results of the ball-end-mill machining for the vanes are described.

Journal Articles

Fabrication of the new RFQ for the J-PARC linac

Morishita, Takatoshi; Kondo, Yasuhiro; Hasegawa, Kazuo; Naito, Fujio*; Yoshioka, Masakazu*; Matsumoto, Hiroshi*; Hori, Yoichiro*; Kawamata, Hiroshi*; Saito, Yoshio*; Baba, Hiroshi*

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.783 - 785, 2010/05

The J-PARC RFQ (length 3.1 m, 4-vane type, 324 MHz) accelerates a negative hydrogen beam from 0.05 MeV to 3 MeV toward the following DTL. The stability of the operating RFQ decreased for a few months at the end of 2008, then, we started a preparation of a new RFQ as a backup machine in the case of RFQ problem. The beam dynamics design of the new RFQ is the same as the current cavity for a quick resumption of operation, however, the engineering and RF designs are changed to improve stability. The processes of the vane machining and the surface treatments have been carefully considered to reduce the discharge problem. The vacuum brazing technique has been chosen for vane jointing. The design of the new RFQ and the fabrication progress is descried in this proceeding.

Journal Articles

Engineering design of RFQ at J-PARC linac

Morishita, Takatoshi; Kondo, Yasuhiro; Hasegawa, Kazuo; Naito, Fujio*; Yoshioka, Masakazu*; Matsumoto, Hiroshi*; Hori, Yoichiro*; Kawamata, Hiroshi*; Saito, Yoshio*; Baba, Hiroshi*; et al.

Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.1047 - 1049, 2010/03

The beam commissioning of J-PARC linac has been started since November 2006. After the scheduled shutdown in summer 2007, the beam is successfully delivered from the linac to the RCS. Since then, a stable beam provision was emphasized. However, the trip in the RFQ was increased at the end of Sept. 2008, then, the stability of the beam operation decreased. To improve this situation, we started to prepare a new RFQ cavity as a backup machine. The basic concept of the engineering design is the simplicity and the effective vacuum pumping aiming at the stable operation. A 3m long cavity is divided into 3 modules longitudinally. A numerical control machining with ball-end mill is chosen for a vane machining. Four vanes are vacuum brazed each other after machining. Each modules are aligned on the platform using a linear motion guide. A basic design of the key components on machining and brazing are described in this proceeding.

Journal Articles

The Electronic structures of fullerene/transition-metal hybrid material

Matsumoto, Yoshihiro; Sakai, Seiji; Naramoto, Hiroshi*; Hirao, Norie*; Baba, Yuji; Shimada, Toshihiro*; Sugai, Isamu; Takanashi, Koki; Maeda, Yoshihito

Materials Research Society Symposium Proceedings, Vol.1081 (Internet), 6 Pages, 2008/03

Recently, we have found the appearance of substantial MR ratio (80%) in a C$$_{60}$$/Co hybrid material. Such the MR ratio cannot be explained enough only by tunnel conduction through Co grains. Therefore, to obtain information about electronic structures of C$$_{60}$$/Co hybrid material is necessary. Absorption spectra of C$$_{60}$$Co are different from that of pristine C$$_{60}$$. In particular, peak intensity corresponding to $$pi$$ $$^*$$(LUMO) $$leftarrow$$ C 1s excitation of C$$_{60}$$Co is clearly attenuated. In addition, C 1s photoelectron peak of C$$_{60}$$Co slightly shifted to lower binding energy compared to that of pristine C$$_{60}$$. These results indicate that 3d electron of Co transfers to $$pi$$ $$^*$$ orbital of C$$_{60}$$ and new electronic states are formed in the C$$_{60}$$-Co compound. In fact, XPS spectra of valence excitation region also demonstrate the formation of hybrid orbital near the Fermi level due to the coupling of C$$_{60}$$ and Co.

Journal Articles

Comparative study of structures and electrical properties in cobalt-fullerene mixtures by systematic change of cobalt content

Sakai, Seiji; Naramoto, Hiroshi*; Avramov, P.; Yaita, Tsuyoshi; Lavrentiev, V.; Narumi, Kazumasa; Baba, Yuji; Maeda, Yoshihito

Thin Solid Films, 515(20-21), p.7758 - 7764, 2007/07

 Times Cited Count:24 Percentile:68.43(Materials Science, Multidisciplinary)

A systematic study is performed for the Co content-dependent structure evolution and electrical properties in the cobalt(Co)-fullerene(C$$_{60}$$) mixtures in the broad content region. Raman analysis confirms that the mixture has a saturation composition of Co$$_{5}$$C$$_{60}$$ for the compoundformation. An important role of the covalent Co-C bonds for the characteristic structure and the properties in the Co-C$$_{60}$$ compounds is concluded from the content-dependent peak shifts and the symmetry lowering of C$$_{60}$$. The Co-dilute mixtures exhibit a semiconductive nature represented bythe activated transport from the shallow mid-gap states. The Co-dense mixtures are characterized by hopping conduction (including variable rangehopping) attributed to the Co clusters/nanoparticles in the compound matrix and by the percolated metallic conduction, depending on the Co content.

Journal Articles

Advanced diagnostics for burning plasma experiments

Sasao, Mamiko*; Yamada, Hiroshi*; Baba, Mamoru*; Kondoh, Takashi; Peterson, B. J.*; Kawahata, Kazuo*; Mase, Atsushi*; Yoshikawa, Masayuki*; Azechi, Hiroshi*; Toi, Kazuo*; et al.

Fusion Science and Technology, 51(2T), p.40 - 45, 2007/02

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

Several unexplored physics issues will be studied in burning plasma experiments, planned on ITER in the near future. To carry out these studies, it is essential to develop novel diagnostic systems, such as fusion product measurement systems and high-resolution, high-reliability profile measurement of various plasma parameters. Scientific research on "Advanced Diagnostics for Burning Plasma Experiment" was assigned as a priority area by MEXT in 2004, and more than 20 studies are currently underway under this program. The feasibility of several new diagnostic concepts applicable to ITER is examined and diagnostic components for these systems are now under development.

Journal Articles

Measurement of neutron spectra produced in the forward direction from thick graphite, Al, Fe and Pb targets bombarded by 350 MeV protons

Iwamoto, Yosuke; Taniguchi, Shingo*; Nakao, Noriaki*; Itoga, Toshio*; Nakamura, Takashi*; Nakane, Yoshihiro; Nakashima, Hiroshi; Satoh, Daiki; Yashima, Hiroshi*; Yamakawa, Hiroshi*; et al.

Nuclear Instruments and Methods in Physics Research A, 562(2), p.789 - 792, 2006/06

 Times Cited Count:6 Percentile:43.85(Instruments & Instrumentation)

Neutron energy spectra produced from thick targets play an important role in validation of calculation codes that are employed in the design of spallation neutron sources and the shielding design of accelerator facilities. However, appropriate experimental data were scarce in the forward direction for the incident energy higher than 100 MeV. In this study, neutron spectra at 0 degree from thick targets bombarded with 350 MeV protons were measured by the time-of-flight technique using an NE213. The targets used were graphite, Al, Fe and Pb and their thicknesses were chosen to be a little thicker than the stopping lengths. The experiment was carried out at the TOF course of the RCNP (Research Center of Nuclear Physics) ring cyclotron, Osaka University. The flight path length between center of the target and of an NE213 were 11.4 m for the measurement of low energy neutrons and 95 m for high energy neutrons. The experimental data are compared with the calculated results by using the Monte Carlo transport codes, such as MCNPX and PHITS codes.

Journal Articles

Gamow-Teller decay of the $$T=1$$ nucleus $$^{46}$$Cr

Onishi, Takeo*; Gelberg, A.*; Sakurai, Hiroyoshi*; Yoneda, Kenichiro*; Aoi, Nori*; Imai, Nobuaki*; Baba, Hidetada*; Von Brentano, P.*; Fukuda, Naoki*; Ichikawa, Yuichi*; et al.

Physical Review C, 72(2), p.024308_1 - 024308_7, 2005/08

 Times Cited Count:21 Percentile:77.65(Physics, Nuclear)

no abstracts in English

Journal Articles

Polymeric Co-C$$_{60}$$ compound phase evolved in atomistically mixed thin films

Sakai, Seiji; Naramoto, Hiroshi*; Lavrentiev, V.*; Narumi, Kazumasa; Maekawa, Masaki; Kawasuso, Atsuo; Yaita, Tsuyoshi; Baba, Yuji

Materials Transactions, 46(4), p.765 - 768, 2005/04

 Times Cited Count:17 Percentile:70.79(Materials Science, Multidisciplinary)

A systematic study of the atom-level mixtures between Co and C$$_{60}$$ has made possible to find a new C$$_{60}$$-based compound phase, Co$$_{x}$$C$$_{60}$$ (x$$leq$$5). It is confirmed with the EXAFS analysis and the positron annihilation study that the polymeric structure is developed three-dimensionally by bridging two C$$_{60}$$ molecules with the covalently bonded Co atom.

Journal Articles

Shielding experiments and analyses on proton accelerator facility at TIARA

Nakashima, Hiroshi; Sakamoto, Yukio*; Tanaka, Shunichi; Tanaka, Susumu; Baba, Mamoru*; Nakamura, Takashi*; Hirayama, Hideo*; Shin, Kazuo*; JAERI-Universities Collaboration Working Group for Accelerator Shielding Study

Proceedings of 6th International Meeting on Nuclear Applications of Accelerator Technology (AccApp '03), p.959 - 968, 2003/00

In order to validate shielding design methods on proton accelerator facilities, a series of shielding experiments in several tens of MeV energy region were carried out at the Takasaki Ion Accelerators for Advanced Radiation Application (TIARA) of Japan Atomic Energy Research Institute (JAERI). The experiments include thick target neutron yield (TTY) measurements by charged particles, deep penetration experiments on concrete, steel and polyethylene shields using p-Li monoenergetic neutron source and radiation streaming experiment at a labyrinth of TIARA using p-Cu white neutron source. These experimental results are compared with calculation results with some high-energy particle transport codes such as MCNPX and NMTC/JAERI. The TTY measurements were analyzed by a code developed by Shin with a moving source model, and the streaming experiment was also analyzed by the DUCT-III code based on Shin's equation. This paper reviews the experimental results and the analyses on the results.

Journal Articles

FRL1 is required for petal and sepal development in arabidopsis

Hase, Yoshihiro; Tanaka, Atsushi; Baba, Tomohiro*; Watanabe, Hiroshi

Plant Journal, 24(1), p.21 - 32, 2000/10

 Times Cited Count:47 Percentile:71.66(Plant Sciences)

no abstracts in English

Journal Articles

X-ray absorption studies of anodized monocrystalline 3C-SiC

Monguchi, Takuo*; Fujioka, Hiroshi*; Uragami, Takeshi*; Ono, Kanta*; Baba, Yuji; Oshima, Masaharu*

Journal of the Electrochemical Society, 147(2), p.741 - 743, 2000/02

 Times Cited Count:5 Percentile:23.47(Electrochemistry)

no abstracts in English

Journal Articles

Resonant Auger electron spectroscopy for analysis of the chemical state of phosphorus segregated at SiO$$_{2}$$/Si Interfaces

Oshima, Masaharu*; *; Ono, Kanta*; Fujioka, Hiroshi*; *; Baba, Yuji; Yoshii, Kenji; Sasaki, Teikichi

Journal of Electron Spectroscopy and Related Phenomena, 88-91, p.603 - 607, 1998/00

 Times Cited Count:5 Percentile:25.68(Spectroscopy)

no abstracts in English

JAEA Reports

Experiments on iron shield transmission of quasi-monoenergetic neutrons generated by 43- and 68-MeV protons via the $$^{7}$$Li(P,n) reaction

; Nakao, Noriaki*; Tanaka, Shunichi; Nakamura, Takashi*; Shin, Kazuo*; Tanaka, Susumu; Meigo, Shinichiro; Nakane, Yoshihiro; Takada, Hiroshi; Sakamoto, Yukio; et al.

JAERI-Data/Code 96-005, 46 Pages, 1996/03

JAERI-Data-Code-96-005.pdf:1.54MB

no abstracts in English

Oral presentation

Structures and thermal stabilities of polymeric transition metal-C$$_{60}$$ compounds evolved in atomistically mixed thin films

Sakai, Seiji; Naramoto, Hiroshi; Yaita, Tsuyoshi; Maekawa, Masaki; Kawasuso, Atsuo; Avramov, P.; Narumi, Kazumasa; Baba, Yuji

no journal, , 

no abstracts in English

25 (Records 1-20 displayed on this page)