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Journal Articles

Design and actual performance of J-PARC 3 GeV rapid cycling synchrotron for high-intensity operation

Yamamoto, Kazami; Kinsho, Michikazu; Hayashi, Naoki; Saha, P. K.; Tamura, Fumihiko; Yamamoto, Masanobu; Tani, Norio; Takayanagi, Tomohiro; Kamiya, Junichiro; Shobuda, Yoshihiro; et al.

Journal of Nuclear Science and Technology, 32 Pages, 2022/02

 Times Cited Count:0 Percentile:0.03(Nuclear Science & Technology)

In the Japan Proton Accelerator Research Complex, the purpose of the 3 GeV rapid cycling synchrotron (RCS) is to accelerate a 1 MW, high-intensity proton beam. To achieve beam operation at a repetition rate of 25 Hz at high intensities, the RCS was elaborately designed. After starting the RCS operation, we carefully verified the validity of its design and made certain improvements to establish a reliable operation at higher power as possible. Consequently, we demonstrated beam operation at a high power, namely, 1 MW. We then summarized the design, actual performance, and improvements of the RCS to achieve a 1 MW beam.

Journal Articles

Coupled bunch instability and its cure at J-PARC RCS

Shobuda, Yoshihiro; Saha, P. K.; Hotchi, Hideaki; Harada, Hiroyuki; Takayanagi, Tomohiro; Tamura, Fumihiko; Tani, Norio; Togashi, Tomohito; Toyama, Takeshi*; Watanabe, Yasuhiro; et al.

Proceedings of 8th International Particle Accelerator Conference (IPAC '17) (Internet), p.2946 - 2949, 2017/05

no abstracts in English

Journal Articles

Progress of injection energy upgrade project for J-PARC RCS

Hayashi, Naoki; Harada, Hiroyuki; Horino, Koki; Hotchi, Hideaki; Kamiya, Junichiro; Kinsho, Michikazu; Saha, P. K.; Shobuda, Yoshihiro; Takayanagi, Tomohiro; Tani, Norio; et al.

Proceedings of 4th International Particle Accelerator Conference (IPAC '13) (Internet), p.3833 - 3835, 2014/07

no abstracts in English

Journal Articles

Beam emittance control by changing injection painting area in a pulse-to-pulse mode in the 3-GeV rapid cycling synchrotron of Japan Proton Accelerator Research Complex

Saha, P. K.; Harada, Hiroyuki; Hayashi, Naoki; Horino, Koki; Hotchi, Hideaki; Kinsho, Michikazu; Takayanagi, Tomohiro; Tani, Norio; Togashi, Tomohito; Ueno, Tomoaki; et al.

Physical Review Special Topics; Accelerators and Beams, 16(12), p.120102_1 - 120102_11, 2013/12

 Times Cited Count:4 Percentile:35.35(Physics, Nuclear)

Journal Articles

Performance of the bump system for the painting injection at J-PARC

Takayanagi, Tomohiro; Ueno, Tomoaki; Togashi, Tomohito; Harada, Hiroyuki*; Saha, P. K.; Hotchi, Hideaki; Kinsho, Michikazu; Kamiya, Junichiro; Watanabe, Masao; Yoshimoto, Masahiro; et al.

Proceedings of 2009 Particle Accelerator Conference (PAC '09) (DVD-ROM), p.1507 - 1509, 2009/05

The shift bump-magnets, which give a constant bump field in a horizontal plane during injection, comprise four magnets connected in series. However, the total integrated magnetic field over the four magnets is not zero because of the magnetic field interferences with the neighboring quadrupole magnets. So the gap of each magnet was adjusted by inserting thin insulators into the splitting plane of the side yoke so that the field integration becomes zero. The closed orbit distortion due to the field imbalances was then confirmed to be less than 1 mm. Another four paint bump-magnets are connected to their own power supplies, separately. The excitation of each magnet is calibrated by using the beam so that the created bump orbit satisfies the position and inclination at the injection point, and there are no orbit distortions outside the injection area.

Journal Articles

Initial oxidation of Si(110) as studied by real-time synchrotron-radiation X-ray photomission spectroscopy

Suemitsu, Maki*; Yamamoto, Yoshihisa*; Togashi, Hideaki*; Enta, Yoshiharu*; Yoshigoe, Akitaka; Teraoka, Yuden

Journal of Vacuum Science and Technology B, 27(1), p.547 - 550, 2009/02

 Times Cited Count:4 Percentile:30.58(Engineering, Electrical & Electronic)

Initial oxidation processes of the Si(110) surface and the chemical bonding states of silicon atoms in the initial oxides have been investigated by using real-time synchrotron-radiation photoemission spectroscopy. Time evolutions of the Si$$^{n+}$$ ($$n$$=1-4) components in the Si 2$$p$$ spectrum indicates that the Si$$^{3+}$$ component always overwhelms the Si$$^{4+}$$ component during the oxidation up to one monolayer. This is in sharp contrast to the Si(001) surface where Si$$^{4+}$$ is always larger than Si$$^{3+}$$. The dominance of the Si$$^{3+}$$ component is related to presence of two types of bonds on the Si(110) surface and to their possible different reactivity against insertion of oxygen atoms.

Journal Articles

SR-PES and STM observation of metastable chemisorption state of oxygen on Si(110)-16$$times$$2 surface

Yamamoto, Yoshihisa*; Togashi, Hideaki*; Kato, Atsushi*; Takahashi, Yuya*; Konno, Atsushi*; Teraoka, Yuden; Yoshigoe, Akitaka; Asaoka, Hidehito; Suemitsu, Maki*

Applied Surface Science, 254(19), p.6232 - 6234, 2008/07

 Times Cited Count:4 Percentile:22.83(Chemistry, Physical)

The room temperature adsorbed state of oxygen molecules on Si(110)-16$$times$$2 surface and the structural change after a mild annealing has been investigated by synchrotron radiation photoemission spectroscopy. As a result, despite the very small dosage of oxygen, Si$$^{2+}$$ and Si$$^{3+}$$ components already appear in addition to Si$$^{1+}$$. This is likely to be caused by a selective adsorption of O$$_{2}$$ molecules into the vicinity of already oxidized sites. After annealing, we found that binding energy of Si$$^{2+}$$ and Si$$^{3+}$$ increase and approach to their corresponding peak positions of a thermally-grown oxide, and this increase indicates relaxation of the Si-O bond length and Si-O-Si bond angle of metastable oxygen atoms.

Journal Articles

XPS real-time monitoring on the development of Si suboxides during formation of thermal oxides on Si(110) surface

Yamamoto, Yoshihisa*; Togashi, Hideaki*; Konno, Atsushi*; Matsumoto, Mitsutaka*; Kato, Atsushi*; Saito, Eiji*; Suemitsu, Maki*; Teraoka, Yuden; Yoshigoe, Akitaka

Shingaku Giho, 108(80), p.65 - 70, 2008/06

The growth process of thermal oxides on Si(110) surface and the development of their interfacial bonding structures have been investigated by using real-time synchrotron radiation photoemission spectroscopy. As a result, it was clarified that the Si$$^{3+}$$ component in the Si 2p core-level spectra is always much higher than that of Si$$^{4+}$$ for 0-1 mono-layer (ML) oxides on Si(110) surface. Observations on the time-evolution of the O 1s core-level spectrum indicates that the autocatalytic-reaction model proposed for the Si(001) oxidation can be also applicable to the Si(110) oxidation.

Journal Articles

Bonding structure of ultrathin oxides on Si(110) surface

Yamamoto, Yoshihisa*; Togashi, Hideaki*; Kato, Atsushi*; Suemitsu, Maki*; Narita, Yuzuru*; Teraoka, Yuden; Yoshigoe, Akitaka

Materials Research Society Symposium Proceedings, Vol.1074, p.36 - 40, 2008/00

In this study, we have investigated the bonding structure of ultrathin oxide films on Si(110) surface by real-time SR-PES experiments. Experiments were conducted at surface chemistry end-station settled at BL23SU in SPring-8. The oxidation temperature was 813 K and the O$$_{2}$$ pressure was 1.1$$times$$10$$^{-5}$$ Pa. As a result, we found that one of the surface core-level shifts in Si 2p spectrum, related to the 1st and the 2nd layer Si atoms, decreases rapidly, coincident with the rapid initial development of the O1s spectrum. This indicates high reactivity of the Si(110)-16$$times$$2 reconstructed surface with oxygen molecules.

Journal Articles

Observation of initial oxidation on Si(110)-16$$times$$2 surface by scanning tunneling microscopy

Togashi, Hideaki*; Takahashi, Yuya*; Kato, Atsushi*; Konno, Atsushi*; Asaoka, Hidehito; Suemitsu, Maki*

Japanese Journal of Applied Physics, Part 1, 46(5B), p.3239 - 3243, 2007/05

 Times Cited Count:13 Percentile:48.37(Physics, Applied)

On Si(110) surface, the hole mobility is enhanced as compared with that on Si(001) surface. This surface is also to be used in the next-generation three-dimensional devices. We conducted scanning-tunneling-microscopy (STM) observation on the initial oxidation of Si(110)-16$$times$$2 surface. The present result suggests less occurrence of etching under the oxidation condition. There is a possibility to form an abrupt oxide/Si interface on the Si(110) surface.

Journal Articles

Real-time observation of initial thermal oxidation on Si(110)-16$$times$$2 surfaces by O 1s photoemission spectroscopy using synchrotron radiation

Suemitsu, Maki*; Kato, Atsushi*; Togashi, Hideaki*; Konno, Atsushi*; Yamamoto, Yoshihisa*; Teraoka, Yuden; Yoshigoe, Akitaka; Narita, Yuzuru*; Enta, Yoshiharu*

Japanese Journal of Applied Physics, Part 1, 46(4B), p.1888 - 1890, 2007/04

 Times Cited Count:12 Percentile:45.97(Physics, Applied)

Initial oxidation of Si(110) surface has been investigated by using real-time X-ray photoemission spectroscopy. The time evolution of the O 1s spectrum shows occurrence of rapid oxidation just after the introduction of the oxygen molecules, which is evidenced by the considerable peak intensity corresponding to oxygen exposure of as low as 1.5L (1L=1.33$$times$$10$$^{-4}$$ Pa s). This initial oxide is dominated by a state with a relatively low binding energy, which is gradually replaced by a state with a relatively high binding energy with the increase of the oxygen exposure, resulting in the low-KE shift of the O 1s peak. Comparison with previously reported O 1s spectra from dry-oxidized Si(111) surface suggests oxidation at or around the adatoms of Si(110)-16$$times$$2 clean surface as a likely oxidation state for this low-binding-energy peak.

Journal Articles

XPS and STM studies on initial oxidation of Si(110)-16$$times$$2

Suemitsu, Maki*; Togashi, Hideaki*; Kato, Atsushi*; Takahashi, Yuya*; Konno, Atsushi*; Yamamoto, Yoshihisa*; Teraoka, Yuden; Yoshigoe, Akitaka; Asaoka, Hidehito

Materials Research Society Symposium Proceedings, Vol.996, p.19 - 25, 2007/00

From its high hole mobility, as well as its inevitable usage as an active layer in multi-gated FETs, Si(110) surface is expected to play a crucial role in the next generation CMOS devices. We have investigated the initial oxidation of Si(110) surface by using SR-XPS and STM. Reflecting its atomistic structure of the 16$$times$$2 reconstruction, initial oxidation of Si(110) surface shows a unique behavior which is not observed on other surfaces like (111) and (001).

Journal Articles

Comparison of initial oxidation between Si(110) and Si(100) surfaces; From real-time photoemission spectroscopy

Suemitsu, Maki*; Kato, Atsushi*; Togashi, Hideaki*; Konno, Atsushi*; Yamamoto, Yoshihisa*; Teraoka, Yuden; Yoshigoe, Akitaka; Narita, Yuzuru*

Shingaku Giho, 106(108), p.61 - 63, 2006/06

no abstracts in English

Journal Articles

Real-time observation of initial thermal oxidation on Si(110)-16$$times$$2 surface by photoemission spectroscopy

Suemitsu, Maki*; Kato, Atsushi*; Togashi, Hideaki*; Konno, Atsushi*; Yamamoto, Yoshihisa*; Teraoka, Yuden; Yoshigoe, Akitaka; Enta, Yoshiharu*; Narita, Yuzuru*

ECS Transactions, 3(2), p.311 - 316, 2006/00

Initial thermal oxidation of Si(110) surface has been investigated by using real-time X-ray photoemission spectroscopy with synchrotron radiation. The Si(110) initial oxidation is characterized by presence of a rapid oxidation just after the introduction of gaseous oxygen molecules. Peak separation of the O1s photoemission spectra suggests the presence of at least two distinct oxidation sites on the surface, which may reflect the complicated surface structure of the Si(110)-16$$times$$2 reconstruction.

Journal Articles

Nucleation of oxides during dry oxidation of Si(001)-2$$times$$1 studied by scanning tunneling microscopy

Togashi, Hideaki*; Asaoka, Hidehito; Yamazaki, Tatsuya; Suemitsu, Maki*

Japanese Journal of Applied Physics, Part 2, 44(45), p.L1377 - L1380, 2005/10

 Times Cited Count:3 Percentile:14.17(Physics, Applied)

no abstracts in English

Oral presentation

Mode change in the initial growth of oxide islands during dry oxidation of Si(001)-2$$times$$1 surface, 2

Togashi, Hideaki*; Suemitsu, Maki*; Asaoka, Hidehito; Yamazaki, Tatsuya

no journal, , 

no abstracts in English

Oral presentation

Effect of dopant on the initial growth mode of oxide islands during dry oxidation of Si(001)-2$$times$$1 surface

Togashi, Hideaki*; Suemitsu, Maki*; Asaoka, Hidehito; Yamazaki, Tatsuya

no journal, , 

no abstracts in English

Oral presentation

Initial oxidation of Si(110) as evaluated with real-time XPS

Suemitsu, Maki*; Kato, Atsushi*; Togashi, Hideaki*; Konno, Atsushi*; Yamamoto, Yoshihisa*; Teraoka, Yuden; Yoshigoe, Akitaka; Narita, Yuzuru*

no journal, , 

Initial kinetics in dry oxidation of Si(110) surface, a key technology in the next-generation CMOS technology, has been investigated by using synchrotron-radiation photoemission spectroscopy. As a result, the uptake curve of the Si(110) oxide in its high-pressure-low-temperature reaction regime is found to consist of three characteristic time domains, in sharp contrast with the single domain obtained on Si(001). The difference is understood in terms of the different atomistic arrangement on the surface.

Oral presentation

Comparison of initial oxidation between Si(110) and Si(100) surfaces; From real-time photoemission spectroscopy

Suemitsu, Maki*; Kato, Atsushi*; Togashi, Hideaki*; Konno, Atsushi*; Yamamoto, Yoshihisa*; Teraoka, Yuden; Yoshigoe, Akitaka; Narita, Yuzuru*

no journal, , 

By using real-time photoemission spectroscopy, kinetics of initial oxidation of Si(110)-16$$times$$2 surface has been investigated and is compared with that of Si(100) surface. Dry oxidation of Si(110) shows rapid initial oxidation just after introduction of the oxygen, which is associated with an O1s state with a weaker binding energy. As the oxidation proceeds, another O1s state with a stronger binding energy develops. The rapid initial oxidation is related to oxidation at or around the Si(111)-like Si adatoms, which are reportedly present in the 16$$times$$2 reconstruction of the Si(110) surface.

Oral presentation

Observation of initial oxidation process on Si(110)-16$$times$$2 by real-time photoemission spectroscopy, 1

Togashi, Hideaki*; Kato, Atsushi*; Yamamoto, Yoshihisa*; Konno, Atsushi*; Suemitsu, Maki*; Teraoka, Yuden; Yoshigoe, Akitaka; Narita, Yuzuru*

no journal, , 

Initial oxidation processes of Si(110) surface have not been studied although they are important for the next generation device. Now we observed time evolution of oxygen coverage at the Si(110)-16$$times$$2 surface in the initial oxidation region by using real-time photoemission spectroscopy with synchrotron radiation. As a conclusion, rapid initial oxidation processes, in which several tens per cent of the surface was oxidized just after oxygen exposure, were found in experimental conditions of 813 K and oxygen pressure of 1.1$$times$$10$$^{-5}$$ Pa. Such a rapid initial oxidation process has not been observed in the initial oxidation of Si(100)-2$$times$$1 surface. This phenomenon may be related with adatom clusters, which exist periodically on the Si(110)-16$$times$$2 surface. For example, An adatom cluster, which consists of five Si atoms, shares 0.25 ML on the Si(110)-16$$times$$2 reconstruction surface in the pentagon-pair model. This model consistents with the initial oxygen coverage obtained in this experiment.

48 (Records 1-20 displayed on this page)