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Journal Articles

Quasifree neutron knockout reaction reveals a small $$s$$-Orbital component in the Borromean nucleus $$^{17}$$B

Yang, Z. H.*; Kubota, Yuki*; Corsi, A.*; Yoshida, Kazuki; Sun, X.-X.*; Li, J. G.*; Kimura, Masaaki*; Michel, N.*; Ogata, Kazuyuki*; Yuan, C. X.*; et al.

Physical Review Letters, 126(8), p.082501_1 - 082501_8, 2021/02

 Times Cited Count:0 Percentile:100(Physics, Multidisciplinary)

A quasifree ($$p$$,$$pn$$) experiment was performed to study the structure of the Borromean nucleus $$^{17}$$B, which had long been considered to have a neutron halo. By analyzing the momentum distributions and exclusive cross sections, we obtained the spectroscopic factors for $$1s_{1/2}$$ and $$0d_{5/2}$$ orbitals, and a surprisingly small percentage of 9(2)% was determined for $$1s_{1/2}$$. Our finding of such a small $$1s_{1/2}$$ component and the halo features reported in prior experiments can be explained by the deformed relativistic Hartree-Bogoliubov theory in continuum, revealing a definite but not dominant neutron halo in $$^{17}$$B. The present work gives the smallest $$s$$- or $$p$$-orbital component among known nuclei exhibiting halo features and implies that the dominant occupation of $$s$$ or $$p$$ orbitals is not a prerequisite for the occurrence of a neutron halo.

Journal Articles

Spallation and fragmentation cross sections for 168 MeV/nucleon $$^{136}$$Xe ions on proton, deuteron, and carbon targets

Sun, X. H.*; Wang, H.*; Otsu, Hideaki*; Sakurai, Hiroyoshi*; Ahn, D. S.*; Aikawa, Masayuki*; Fukuda, Naoki*; Isobe, Tadaaki*; Kawakami, Shunsuke*; Koyama, Shumpei*; et al.

Physical Review C, 101(6), p.064623_1 - 064623_12, 2020/06

 Times Cited Count:1 Percentile:45.53(Physics, Nuclear)

The spallation and fragmentation reactions of $$^{136}$$Xe induced by proton, deuteron and carbon at 168 MeV/nucleon were studied at RIKEN Radioactive Isotope Beam Factory via the inverse kinematics technique. The cross sections of the lighter products are larger in the carbon-induced reactions due to the higher total kinetic energy of carbon. The energy dependence was investigated by comparing the newly obtained data with previous results obtained at higher reaction energies. The experimental data were compared with the results of SPACS, EPAX, PHITS and DEURACS calculations. These data serve as benchmarks for the model calculations.

Journal Articles

How different is the core of $$^{25}$$F from $$^{24}$$O$$_{g.s.}$$ ?

Tang, T. L.*; Uesaka, Tomohiro*; Kawase, Shoichiro; Beaumel, D.*; Dozono, Masanori*; Fujii, Toshihiko*; Fukuda, Naoki*; Fukunaga, Taku*; Galindo-Uribarri. A.*; Hwang, S. H.*; et al.

Physical Review Letters, 124(21), p.212502_1 - 212502_6, 2020/05

 Times Cited Count:5 Percentile:12.63(Physics, Multidisciplinary)

The structure of a neutron-rich $$^{25}$$F nucleus is investigated by a quasifree ($$p,2p$$) knockout reaction. The sum of spectroscopic factors of $$pi 0d_{5/2}$$ orbital is found to be 1.0 $$pm$$ 0.3. The result shows that the $$^{24}$$O core of $$^{25}$$F nucleus significantly differs from a free $$^{24}$$O nucleus, and the core consists of $$sim$$35% $$^{24}$$O$$_{rm g.s.}$$, and $$sim$$65% excited $$^{24}$$O. The result shows that the $$^{24}$$O core of $$^{25}$$F nucleus significantly differs from a free $$^{24}$$O nucleus. The result may infer that the addition of the $$0d_{5/2}$$ proton considerably changes the neutron structure in $$^{25}$$F from that in $$^{24}$$O, which could be a possible mechanism responsible for the oxygen dripline anomaly.

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:5 Percentile:28.48(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

Characterisation of structural similarities of precipitates in Mg-Zn and Al-Zn-Mg alloys systems

Bendo, A.*; Maeda, Tomoyoshi*; Matsuda, Kenji*; Lervik, A.*; Holmestad, R.*; Marioara, C. D.*; Nishimura, Katsuhiko*; Nunomura, Norio*; Toda, Hiroyuki*; Yamaguchi, Masatake; et al.

Philosophical Magazine, 99(21), p.2619 - 2635, 2019/07

 Times Cited Count:9 Percentile:19.26(Materials Science, Multidisciplinary)

Journal Articles

Measurements of electron-induced neutrons as a tool for determination of electron temperature of fast electrons in the task of optimization laser-produced plasma ions acceleration

Sakaki, Hironao; Nishiuchi, Mamiko; Maeda, Shota; Sagisaka, Akito; Pirozhkov, A. S.; Pikuz, T.; Faenov, A.*; Ogura, Koichi; Fukami, Tomoyo; Matsukawa, Kenya*; et al.

Review of Scientific Instruments, 85(2), p.02A705_1 - 02A705_4, 2014/02

 Times Cited Count:2 Percentile:86.07(Instruments & Instrumentation)

High intensity laser-plasma interaction has attracted considerable interest for a number of years. The laser-plasma interaction is accompanied by generation of various charged particle beams. Results of simultaneous novel measurements of electron-induced photonuclear neutrons (photoneutron), which are a diagnostic of the laser-plasma interaction, are proposed to use for optimization of the laser-plasma ion generation. The proposed method is demonstrated by the laser irradiation with the intensity os 1$$times$$10$$^{21}$$ W/cm$$^{2}$$ on the metal foil target. The photoneutrons are measured by using NE213 liquid scintillation detectors. Heavy-ion signal is registered with the CR39 track detector simultaneously. The measured signals of the electron-induced photoneutrons are well reproduced by using the Particle and Heavy Ion Transport code System (PHITS). The results obtained provide useful approach for analyzing the various laser based ion beams.

Journal Articles

Test beam-line for laser-driven proton therapy

Sakaki, Hironao; Nishiuchi, Mamiko; Hori, Toshihiko; Bolton, P.; Yogo, Akifumi; Ogura, Koichi; Sagisaka, Akito; Pirozhkov, A. S.; Orimo, Satoshi; Kondo, Kiminori; et al.

Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.312 - 315, 2010/08

The beam transport test is carried out through the test beam line of the laser-driven proton accelerator which consists of the phase rotation cavity, PMQ, and bending magnet. The laser system used is J-KAREN at JAEA. The final transmitted bunch duration and transverse profile are well predicted by the PARMILA particle transport code by assuming relatively low initial current of the proton beam. The most probable explanation for this is the space charge neutralization by the laser-plasma-electrons.

Journal Articles

Measured and simulated transport of 1.9 MeV laser-accelerated proton bunches through an integrated test beam line at 1 Hz

Nishiuchi, Mamiko; Sakaki, Hironao; Hori, Toshihiko; Bolton, P.; Ogura, Koichi; Sagisaka, Akito; Yogo, Akifumi; Mori, Michiaki; Orimo, Satoshi; Pirozhkov, A. S.; et al.

Physical Review Special Topics; Accelerators and Beams, 13(7), p.071304_1 - 071304_7, 2010/07

 Times Cited Count:25 Percentile:17.34(Physics, Nuclear)

A laser-driven repetition-rated 1.9 MeV proton beam line composed of permanent quadrupole magnets (PMQs), a radio frequency (rf) phase rotation cavity, and a tunable monochromator is developed to evaluate and to test the simulation of laser-accelerated proton beam transport through an integrated system for the first time. In addition, the proton spectral modulation and focusing behavior of the rf phase rotationcavity device is monitored with input from a PMQ triplet. In the 1.9 MeV region we observe very weakproton defocusing by the phase rotation cavity. The final transmitted bunch duration and transverse profile are well predicted by the PARMILA particle transport code. The transmitted proton beam duration of 6 ns corresponds to an energy spread near 5% for which the transport efficiency is simulated to be 10%. The predictive capability of PARMILA suggests that it can be useful in the design of future higher energy transport beam lines as part of an integrated laser-driven ion accelerator system.

Journal Articles

Laser-driven proton accelerator for medical application

Nishiuchi, Mamiko; Sakaki, Hironao; Hori, Toshihiko; Bolton, P.; Ogura, Koichi; Sagisaka, Akito; Yogo, Akifumi; Mori, Michiaki; Orimo, Satoshi; Pirozhkov, A. S.; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.88 - 90, 2010/05

The concept of a compact ion particle accelerator has become attractive in view of recent progress in laser-driven ion acceleration. We report here the recent progress in the laser-driven proton beam transport at the Photo Medical Research Center (PMRC) at JAEA, which is established to address the challenge of laser-driven ion accelerator development for ion beam cancer therapy.

Journal Articles

A New method for separating the $$D$$$$_{3}$$ and $$C$$$$_{2v}$$ isomers of C$$_{78}$$

Han, A. H.*; Wakahara, Takatsugu*; Maeda, Yutaka*; Akasaka, Takeshi*; Fujitsuka, Mamoru*; Ito, Osamu*; Yamamoto, Kazunori; Kako, Masahiro*; Kobayashi, Kaoru*; Nagase, Shigeru*

New Journal of Chemistry, 33(3), p.497 - 500, 2009/03

 Times Cited Count:7 Percentile:65.09(Chemistry, Multidisciplinary)

A new chemical method can be applied to isolate the isomers of C$$_{78}$$. The photochemical cycloaddition of a mixture of C$$_{78}$$($$D$$$$_{3}$$) and C$$_{78}$$($$C$$$$_{2v}$$) with disilirane affords only the mono-adduct of the $$C$$$$_{2v}$$ isomer of C$$_{78}$$. The counter part (C$$_{78}$$($$D$$$$_{3}$$)) does not give the mono-adduct with disilirane. The $$D$$$$_{3}$$ isomer itself and the adduct of the $$C$$$$_{2v}$$ isomer of C$$_{78}$$ with disilirane was easily separated by a HPLC procedure. A facile oxidative desilylation of the adduct took place, resulting in the formation of pristine C$$_{78}$$($$C$$$$_{2v}$$). In this context, the separation and the isolation of two isomers of C$$_{78}$$($$C$$$$_{2v}$$) and C$$_{78}$$($$D$$$$_{3}$$) were successfully accomplished by using a silylation-oxidative desilylation process.

Journal Articles

Density-functional theory study of the electronic structure of thin Si/SiO$$_{2}$$ quantum nanodots and nanowires

Avramov, P.; Kuzubov, A. A.*; Fedorov, A. S.*; Sorokin, P. B.*; Tomilin, F. N.*; Maeda, Yoshihito

Physical Review B, 75(20), p.205427_1 - 205427_8, 2007/05

 Times Cited Count:16 Percentile:39.86(Materials Science, Multidisciplinary)

The atomic and electronic structures of a set of proposed pentagonal thin (1.6 nm in diameter) Si/SiO$$_{2}$$ quantum nanodots (QDs) and nanowires (NWs) with narrow interface, as well as parent metastable Si structures (1.2 nm in diameter), were studied using cluster B3LYP/6-31G$$^{*}$$ and periodic boundary condition (PBC) plane-wave (PW) pseudopotential (PP) local-density approximation methods. The total density of states (TDOS) of the smallest quasispherical QD (Si$$_{85}$$) corresponds well to the PBC PW PP LDA TDOS of the crystalline Si. The elongated SiQDs and SiNWs demonstrate the metallic nature of the electronic structure. The surface oxidized layer opens the band gap in the TDOS of the Si/SiO$$_{2}$$ species. The top of the valence band and the bottom of conduction band of the particles are formed by the Si core derived states. The theoretical band gap width is determined by the length of the Si/SiO$$_{2}$$ clusters and describes the size confinement effect in the experimental photoluminescence spectra of the silica embedded nanocrystalline Si with high accuracy.

Journal Articles

The Connection between $$gamma$$-ray bursts and extremely metal-poor stars; Black hole-forming supernovae with relativistic jets

Tominaga, Nozomu*; Maeda, Keiichi*; Umeda, Hideyuki*; Nomoto, Kenichi*; Tanaka, Masaomi*; Iwamoto, Nobuyuki; Suzuki, Tomoharu*; Mazzali, P. A.*

Astrophysical Journal, 657(2, Part2), p.L77 - L80, 2007/03

 Times Cited Count:104 Percentile:7.7(Astronomy & Astrophysics)

Long-duration $$gamma$$-ray bursts (GRBs) are thought to be connected with luminous and energetic Type Ic supernovae [SNe, called hypernovae (HNe)] resulting from the black-hole (BH) forming collapse of massive stars. For GRBs 060505 and 060614, however, the expected SNe have not been detected. The upper limits to the SN brightness are about 100 times fainter than GRB-associated HNe (GRB-HNe), corresponding to the upper limits to the ejected $$^{56}$$Ni masses of $$M(^{56}$$Ni)$$sim 10^{-3}M_odot$$. SNe with a small amount of $$^{56}$$Ni ejection are observed as faint Type II SNe. HNe and faint SNe are thought to be responsible for the formaion of extremely metal-poor (EMP) stars. A relativistic jet-induced BH forming explosion of the 40$$M_odot$$ star is investigated and hydrodynamic and nucleosynthetic models are presented. These models can explain both GRB-HNe and GRBs without bright SNe in a unified manner. We suggest that GRBs without bright SNe are likely to synthesize $$M(^{56}$$Ni)$$sim 10^{-4}-10^{-3}M_odot$$ or $$sim 10^{-6}M_odot$$.

Journal Articles

Band-gap unification of partially Si-substituted single-wall carbon nanotubes

Avramov, P.; Sorokin, P. B.*; Fedorov, A. S.*; Fedorov, D. G.*; Maeda, Yoshihito

Physical Review B, 74(24), p.245417_1 - 245417_8, 2006/12

 Times Cited Count:15 Percentile:41.47(Materials Science, Multidisciplinary)

The atomic and electronic structure of a set of pristine single wall SiC nanotubes as well as Si-substituted carbon nanotubes and a SiC sheet was studied by the LDA plane wave band structure calculations. Consecutive substitution of carbon atoms by Si leads to a gap opening in the energetic spectrum of the metallic (8,8) SWCNT with approximately quadratic dependence of the band gap upon the Si concentration. The same substitution for the semiconductor (10,0) SWCNT results in a band gap minimum (0.27 eV) at $$sim$$25% of Si concentration. In the Si concentration region of 12-18%, both types of nanotubes have less than 0.5 eV direct band gaps at the $$Gamma$$-$$Gamma$$ point. The calculation of the chiral (8,2) SWSi$$_{0.15}$$C$$_{0.85}$$NT system gives a similar (0.6 eV) direct band gap. The regular distribution of Si atoms in the atomic lattice is by $$sim$$0.1 eV/atom energetically preferable in comparison with a random distribution. Time dependent DFT calculations showed that the silicon substitution sufficiently increases (roughly by one order of magnitude) the total probability of optical transitions in the near infrared region, which is caused by the opening of the direct band gap in metallic SWCNTs, the unification of the nature and energy of band gaps of all SWCNT species, the large values of $$<$$Si3$$it{p}$$$$|{it r}|$$Si3$$it{s}$$$$>$$ radial integrals and participation of Si3$$it{d}$$ states in chemical bonding in both valence and conductance bands.

Journal Articles

Field tests on migration of TRU-nuclide, 2; Migration test for engineered barrier materials in aerated soil

Maeda, Toshikatsu; Tanaka, Tadao; Mukai, Masayuki; Ogawa, Hiromichi; Yamaguchi, Tetsuji; Munakata, Masahiro; Matsumoto, Junko; Kozai, Naofumi; Bamba, Tsunetaka; Fan, Z.*; et al.

Nippon Genshiryoku Gakkai Wabun Rombunshi, 2(3), p.336 - 341, 2003/09

no abstracts in English

Journal Articles

Irradiation effects on MgB$$_{2}$$ bulk samples and formation of columner defects on high-Tc supercoductor

Okayasu, Satoru; Sasase, Masato; Hojo, Kiichi; Chimi, Yasuhiro; Iwase, Akihiro; Ikeda, Hiroshi*; Yoshizaki, Ryozo*; Kambara, Tadashi*; Sato, H.*; Hamatani, Yutaro*; et al.

Physica C, 382(1), p.104 - 107, 2002/10

 Times Cited Count:26 Percentile:24.85(Physics, Applied)

no abstracts in English

Journal Articles

Interlayer phase correlation of the vortex system around the coupling transition in Bi$$_{2}$$Sr$$_{2}$$CaCu$$_{2}$$Oy containing columnar defects

*; Hanaguri, T.*; *; Maeda, A.*; Sasase, Masato; Hojo, Kiichi; Steel, D. G.*; Lee, J. U.*; Hofman, D. J.*

Physical Review B, 59(17), p.11568 - 11574, 1999/00

 Times Cited Count:8 Percentile:53.24(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

In-plane microwave conductivity and quasiparticle scattering rate of superconducting high-Tc cuprates

*; *; Maeda, A.*; Asaoka, Hidehito; Takei, Humihiko*; *; *; *; *; *; et al.

Journal of the Physical Society of Japan, 65(10), p.3266 - 3273, 1996/00

 Times Cited Count:16 Percentile:27.77(Physics, Multidisciplinary)

no abstracts in English

Journal Articles

Nonlinear meissner effect in double layered high-Tc cuprates investigated by measurement of the penetration depth

Maeda, A.*; *; *; *; *; *; *; Asaoka, Hidehito; *; *; et al.

Journal of the Physical Society of Japan, 65(11), p.3638 - 3645, 1996/00

 Times Cited Count:21 Percentile:23.35(Physics, Multidisciplinary)

no abstracts in English

Journal Articles

c-axis microwave conductivity of YBa$$_{2}$$Cu$$_{3}$$O$$_{7-delta}$$ in the superconducting state

*; *; *; Maeda, A.*; Asaoka, Hidehito; *

Physical Review B, 51(2), p.1401 - 1405, 1995/01

 Times Cited Count:41 Percentile:17.24(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Microwave properties perpendicular to the CuO$$_{2}$$ planes

*; *; Maeda, A.*; Tamegai, Tsuyoshi*; *; *; *; Asaoka, Hidehito; *

Physica C, 235-240, p.1819 - 1820, 1994/00

 Times Cited Count:2 Percentile:78.67(Physics, Applied)

no abstracts in English

40 (Records 1-20 displayed on this page)