Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 37

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Magnetic and electronic properties of URu$$_2$$Si$$_2$$ revealed by comparison with nonmagnetic references ThRu$$_2$$Si$$_2$$ and LaRu$$_2$$Si$$_2$$

Emi, Naoya*; Hamabata, Ryosuke*; Nakayama, Daisuke*; Miki, Toshihiro*; Koyama, Takehide*; Ueda, Koichi*; Mito, Takeshi*; Kohori, Yo*; Matsumoto, Yuji*; Haga, Yoshinori; et al.

Journal of the Physical Society of Japan, 84(6), p.063702_1 - 063702_4, 2015/06

 Times Cited Count:10 Percentile:64.05(Physics, Multidisciplinary)

Journal Articles

Recent progress in the energy recovery linac project in Japan

Sakanaka, Shogo*; Akemoto, Mitsuo*; Aoto, Tomohiro*; Arakawa, Dai*; Asaoka, Seiji*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2338 - 2340, 2010/05

Future synchrotron light source using a 5-GeV energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting R&D efforts for that. We are developing high-brightness DC photocathode guns, two types of cryomodules for both injector and main superconducting (SC) linacs, and 1.3 GHz high CW-power RF sources. We are also constructing the Compact ERL (cERL) for demonstrating the recirculation of low-emittance, high-current beams using above-mentioned critical technologies.

Journal Articles

972-MHz RF digital feedback control system for J-PARC linac

Kobayashi, Tetsuya; Michizono, Shinichiro*; Fang, Z.*; Matsumoto, Toshihiro*; Suzuki, Hiroyuki; Yamaguchi, Seiya*; Okada, Yoshihito*

Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.1068 - 1070, 2010/03

A 972-MHz RF system is being developed for 400-MeV upgrade of the J-PARC linac. The accelerating field stabilities should be less than $$pm$$1% in amplitude and $$pm$$1$$^{circ}$$ in phase. The basic digital LLRF (Low-Level RF) concept is the same as that of the present 324-MHz system with a compact-PCI crate. The main alterations are RF and clock generator (RF&CLK), mixer and I/Q modulator (IQ&Mixer) and digital LLRF algorithm. Since the typical decay time of the new system is faster (because its operational frequency is higher than that of the present 324-MHz cavity), chopped beam compensation is essential. The performance study of the digital feedback system with a cavity simulator is summarized.

Journal Articles

Digital feedback control for 972 MHz RF system of J-PARC linac

Michizono, Shinichiro*; Fang, Z.*; Matsumoto, Toshihiro*; Yamaguchi, Seiya*; Kobayashi, Tetsuya; Okada, Yoshihito*

Proceedings of 2009 Particle Accelerator Conference (PAC '09) (DVD-ROM), p.2201 - 2203, 2009/05

Upgrade of J-PARC linac has been planed using 972 MHz rf system. The rf eld regulation is required to be less than $$pm$$ 1% in amplitude and $$pm$$ 1$$^{circ}$$. in phase. The basic digital llrf concept is same as the present 324 MHz llrf system using a compact PCI crate. The main alterations are rf and clock generator (RF&LK), mixer and IQ modulator (IQ&Mixer) and digital llrf algorithm. Since the typical decay time is faster (due to higher operational frequency than present 324 MHz cavity), chopped beam compensation is one of the main concerns. Performance of the digital feedback system using a cavity simulator is summarized.

Journal Articles

X-ray absorption spectroscopy and magnetic circular dichroism in codeposited C$$_{60}$$-Co films with giant tunnel magnetoresistance

Matsumoto, Yoshihiro; Sakai, Seiji; Takagi, Yasumasa*; Nakagawa, Takeshi*; Yokoyama, Toshihiko*; Shimada, Toshihiro*; Mitani, Seiji*; Naramoto, Hiroshi*; Maeda, Yoshihito

Chemical Physics Letters, 470(4-6), p.244 - 248, 2009/03

 Times Cited Count:17 Percentile:54.64(Chemistry, Physical)

Electronic and spin states of the codeposited C$$_{60}$$-Co films with large tunnel magnetoresistance (TMR) effect were investigated with the X-ray absorption and magnetic circular dichroism (MCD) spectroscopies. It is revealed that a C$$_{60}$$-Co compound generated in the C$$_{60}$$-Co films shows the clear MCD signal attributed to the spin-polarized Co 3d states hybridized with C$$_{60}$$ $$pi$$ orbitals. The magnetic response of these Co 3d-derived states agrees well with temperature dependence of the observed MR ratios of the granular C$$_{60}$$-Co films. This suggests the incorporation of the spin-polarized Co 3d-derived states of the C$$_{60}$$-Co compound into the observed TMR effect.

Journal Articles

Development of digital low level rf system

Michizono, Shinichiro*; Anami, Shozo*; Katagiri, Hiroaki*; Fang, Z.*; Matsumoto, Toshihiro*; Miura, Takako*; Yano, Yoshiharu*; Yamaguchi, Seiya*; Kobayashi, Tetsuya

Kasokuki, 5(2), p.127 - 136, 2008/07

One of the biggest advantages of the digital low level rf (LLRF) system is its flexibility. Owing to the recent rapid progress in digital devices (such as ADCs and DACs) and telecommunication devices (mixers and IQ modulators), digital LLRF system for accelerators becomes popular in these 10 years. The J-PARC linac LLRF system adopted cPCI crates and FPGA based digital feedback system. After the successful operation of J-PARC linac LLRF system, we developed the STF (ILC test facility in KEK) LLRF system. The future R&D projects (ILC and ERL) are also described from the viewpoints of LLRF.

Journal Articles

Progress in R&D efforts on the energy recovery linac in Japan

Sakanaka, Shogo*; Ago, Tomonori*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; Harada, Kentaro*; Hiramatsu, Shigenori*; Honda, Toru*; et al.

Proceedings of 11th European Particle Accelerator Conference (EPAC '08) (CD-ROM), p.205 - 207, 2008/06

Future synchrotron light sources based on the energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. Our Japanese collaboration team is making efforts for realizing an ERL-based hard X-ray source. We report recent progress in our R&D efforts.

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

Magnetohydrodynamic stability of improved confinement plasmas in JT-60U

Takeji, Satoru; Isayama, Akihiko; Ozeki, Takahisa; Tokuda, Shinji; Ishii, Yasutomo; Oikawa, Toshihiro; Ishida, Shinichi; Kamada, Yutaka; Neyatani, Yuzuru; Yoshino, Ryuji; et al.

Fusion Science and Technology (JT-60 Special Issue), 42(2-3), p.278 - 297, 2002/09

 Times Cited Count:7 Percentile:9.09(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Resistive instabilities in reversed shear discharges and wall stabilization on JT-60

Takeji, Satoru; Tokuda, Shinji; Fujita, Takaaki; Suzuki, Takahiro; Isayama, Akihiko; Ide, Shunsuke; Ishii, Yasutomo; Kamada, Yutaka; Koide, Yoshihiko; Matsumoto, Taro; et al.

Nuclear Fusion, 42(1), p.5 - 13, 2002/01

 Times Cited Count:70 Percentile:89.62(Physics, Fluids & Plasmas)

no abstracts in English

JAEA Reports

Critical experiments and analysis of homogeneous heavy water system; 20% enriched U-D$$_{2}$$O reflector

Hirota, Jitsuya; Kuroi, Hideo; Goto, Yorio; Furuhashi, Akira; Yasuno, Takehiko; Yamamoto, Ken; Mitani, Hiroshi; Obu, Makoto; Ichimori, Toshihiro; Koyama, Kinji; et al.

JAERI 1034, 50 Pages, 1962/08

JAERI-1034.pdf:3.64MB

no abstracts in English

Oral presentation

Alpha radioactivity measurement technology with ionized air type measurement apparatus, 2; Measurement test for decontaminated components

Mita, Yutaka; Matsumura, Toshihiro; Sugitsue, Noritake; Yamaguchi, Hiromi; Sano, Akira*; Naito, Susumu*; Maekawa, Tatsuyuki*; Yoshimura, Yukio*; Matsumoto, Takashi*

no journal, , 

By using Ionized Air Type Measurement Apparatus which was designed to measure clearance level of dismantled large-scale things which generate from nuclear plants, after chemical decontaminating machinery and materials which are used in plants, we experimented on a real-scale measurement of clearance level of them. We evaluated performance of detection and confirm applicability as a system of measurement of clearance level.

Oral presentation

Analysis of magnetic properties in C60-Co nanogranular thin film by XMCD spectroscopy

Matsumoto, Yoshihiro; Sakai, Seiji; Naramoto, Hiroshi*; Takagi, Yasumasa*; Nakagawa, Takeshi*; Shimada, Toshihiro*; Yokoyama, Toshihiko*; Maeda, Yoshihito

no journal, , 

no abstracts in English

Oral presentation

Giant TMR effect and spin states of C$$_{60}$$-Co thin films

Sakai, Seiji; Matsumoto, Yoshihiro; Sugai, Isamu*; Mitani, Seiji*; Takanashi, Koki; Takagi, Yasumasa*; Nakagawa, Takeshi*; Yokoyama, Toshihiko*; Shimada, Toshihiro*; Maeda, Yoshihito

no journal, , 

no abstracts in English

Oral presentation

Electronic and spin states and giant tunnel magnetoresistance effect in C$$_{60}$$-Co hybrid films

Sakai, Seiji; Matsumoto, Yoshihiro; Sugai, Isamu*; Mitani, Seiji*; Takanashi, Koki; Takagi, Yasumasa*; Nakagawa, Takeshi*; Yokoyama, Toshihiko*; Shimada, Toshihiro*; Naramoto, Hiroshi*; et al.

no journal, , 

no abstracts in English

Oral presentation

Soft X-ray circular dichroism study of electronic and magnetic states in C$$_{60}$$-Co mixture film

Matsumoto, Yoshihiro; Sakai, Seiji; Naramoto, Hiroshi*; Nakagawa, Takeshi*; Takagi, Yasumasa*; Yokoyama, Toshihiko*; Takanashi, Koki; Mitani, Seiji*; Shimada, Toshihiro*; Maeda, Yoshihito

no journal, , 

no abstracts in English

Oral presentation

Electronic and magnetic states of codeposited C$$_{60}$$-Co films with giant tunnel magnetoresistance effect

Matsumoto, Yoshihiro; Sakai, Seiji; Naramoto, Hiroshi*; Nakagawa, Takeshi*; Takagi, Yasumasa*; Yokoyama, Toshihiko*; Shimada, Toshihiro*; Mitani, Seiji*; Takanashi, Koki; Maeda, Yoshihito

no journal, , 

no abstracts in English

Oral presentation

X-ray magnetic circular dichroism of codeposited C60-Co films with giant tunnel magnetoresistance

Matsumoto, Yoshihiro; Sakai, Seiji; Naramoto, Hiroshi*; Nakagawa, Takeshi*; Takagi, Yasumasa*; Yokoyama, Toshihiko*; Hirao, Norie; Baba, Yuji; Shimada, Toshihiro*; Maeda, Yoshihito

no journal, , 

Recently, we have found that the codeposited C60-Co films where Co nanoparticles are dispersed into the matrix of the C60-Co compound show large tunnel magnetoresistanene (TMR) effects at low temperatures. The observed MR ratios cannot be explained by a spin-polarization of crystalline Co, so it is expected that the C60-Co compound mediates an enhancing effects to the spin-dependent transport in the films. In the present work, we have investigated the spin states of the C60-Co films by X-ray magnetic circular dichroism spectroscopy. As the results, MCD spectra of the C60-Co compound show the sensitivity to the sample temperature, which is consistent to the temperature dependence of MR ratios. This indicates clearly that spin-polarized states of the C60-Co compound influences the degree of spin-dependent transport in the films.

Oral presentation

Electronic and spin states of C$$_{60}$$-Co thin films studied by XPS and X-ray magnetic circular dichroism

Matsumoto, Yoshihiro; Sakai, Seiji; Naramoto, Hiroshi*; Takagi, Yasumasa*; Nakagawa, Takeshi*; Yokoyama, Toshihiko*; Shimada, Toshihiro*; Hirao, Norie; Baba, Yuji; Maeda, Yoshihito

no journal, , 

Oral presentation

Electronic and spin states of C$$_{60}$$-Co thin films studied by XPS and X-ray magnetic circular dichroism

Matsumoto, Yoshihiro; Sakai, Seiji; Takagi, Yasumasa*; Nakagawa, Takeshi*; Yokoyama, Toshihiko*; Mitani, Seiji*; Takanashi, Koki; Shimada, Toshihiro*; Naramoto, Hiroshi*; Maeda, Yoshihito

no journal, , 

no abstracts in English

37 (Records 1-20 displayed on this page)