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Journal Articles

A Diagnosis of intense ion beam by CR-39 detectors analyzing the back scattered particles

Kanasaki, Masato; Yamauchi, Tomoya*; Fukuda, Yuji; Sakaki, Hironao; Hori, Toshihiko*; Tampo, Motonobu; Kurashima, Satoshi; Kamiya, Tomihiro; Oda, Keiji*; Kondo, Kiminori

AIP Conference Proceedings 1465, p.142 - 147, 2012/07

 Times Cited Count:1 Percentile:49.39

A new diagnosis method has been developed utilizing back scattered particles for high energy intense ion beams. The CR-39 detector mounted on the uniform back-scatterer was irradiated with $$^{4}$$He$$^{2+}$$ ions with an energy 25 MeV/n, which is never recorded as etchable track in CR-39. We found that it is possible to diagnose the high energy intense ion beams by analyzing the etch pits created on the rear surface of CR-39 that directly contacted on the back-scatterers. It turns out that most of etch pits in the rear surface are made by the backscattered particles through the investigation of the growth pattern of each etch pit with multi-step etching technique. This method allows simple diagnosis of the ion beam profile and the presence of high energy component of ions beyond the detection threshold limit of the CR-39 in mixed radiation fields such as laser-driven ion acceleration experiments.

Journal Articles

The Diagnosis method for high-energy ion beams using backscattered particles for laser-driven ion acceleration experiments

Kanasaki, Masato; Fukuda, Yuji; Sakaki, Hironao; Hori, Toshihiko; Tampo, Motonobu; Kondo, Kiminori; Kurashima, Satoshi; Kamiya, Tomihiro; Oda, Keiji*; Yamauchi, Tomoya*

Japanese Journal of Applied Physics, 51(5), p.056401_1 - 056401_4, 2012/05

 Times Cited Count:6 Percentile:29.66(Physics, Applied)

A single CR-39 detector mounted on plastic plates is irradiated with a 100 MeV He ion beam. Although the beam energy is much greater than the detection threshold limit of the CR-39 detector, a large number of etch pits having elliptical openings are observed on the rear surface. Detailed investigations reveal that these etch pits are created by heavy ions inelastically backscattered from the plastic plates. This method allows a simple diagnosis of the ion beam profile and the presence of the high-energy component beyond the detection threshold limit of the CR-39 detector, especially in mixed-radiation fields such as laser-driven ion acceleration experiments.

Journal Articles

Quasi-monochromatic pencil beam of laser-driven protons generated using a conical cavity target holder

Nishiuchi, Mamiko; Pirozhkov, A. S.; Sakaki, Hironao; Ogura, Koichi; Esirkepov, T. Z.; Tanimoto, Tsuyoshi; Kanasaki, Masato; Yogo, Akifumi; Hori, Toshihiko; Sagisaka, Akito; et al.

Physics of Plasmas, 19(3), p.030706_1 - 030706_4, 2012/03

 Times Cited Count:6 Percentile:29.7(Physics, Fluids & Plasmas)

A 7 MeV proton beam collimated to 16 mrad containing more than $$10^6$$ particles is experimentally demonstrated by focusing a 2J, 60 fs pulse of a Ti:sapphire laser onto targets of different materials and thicknesses placed in a millimeter scale conical holder. The electric potential induced on the target holder by laser-driven electrons accelerates and dynamically controls a portion of a divergent quasi-thermal proton beam originated from the target, producing a quasi-monoenergetic "pencil" beam.

Journal Articles

Radio frequency plasma transition caused by gas puffing and/or direct current biasing using multiturn internal antenna

Yamauchi, Toshihiko; Kobayashi, Seiji*; Sugibayashi, Hideyuki*; Tachibana, Toshiyuki*; Naito, Shunya*; Kanno, Yoshinori*; Hiruta, Toshihito

Japanese Journal of Applied Physics, 51(1), p.01AA02_1 - 01AA02_7, 2012/01

 Times Cited Count:0 Percentile:0(Physics, Applied)

In the beginning of this study, the RF (radio frequency) plasma by the internal antenna which is in contrast to that of the external antenna, was considered for the transition from the charged coupled plasma (CCP) to the inductively coupled plasma (ICP) not to be observed. On the contrary, in our plasma experiment by using the internal multi-turn RF antenna, the transition phenomenon was observed at the extent of 40 W in RF power. In this experiment, the relation between the gas pressure and the RF power on the transition from CCP to ICP indicated almost the same characteristic as Paschen's law. But the transition physics, or the absorption mechanism of RF power based on the collision dumping, was strongly complex. We have experimentally represented the CCP-ICP transition to study the physics using the original physical technique. Firstly, we changed the CCP into the ICP by the gas control. It was considered that the increase of the electron temperature caused the transition. Secondly, the decrease of gas pressure displayed the same meaning with the longer period of the self-pulse transition. Thirdly, the self-bias caused by RF power and the external bias applied between the RF antenna and the stage were described for the transition physics.

Journal Articles

A New simple diagnosis method for intense ion beam utilizing back scattered particles with PADC track detectors

Kanasaki, Masato; Yamauchi, Tomoya*; Fukuda, Yuji; Sakaki, Hironao; Hori, Toshihiko*; Tampo, Motonobu; Kondo, Kiminori; Kurashima, Satoshi; Kamiya, Tomihiro

Hoshasen, 37(3), p.127 - 132, 2011/10

A diagnosis method has been developed utilizing back scattered particles with the single PADC detector for high energy intense ion beams. The PADC detector mounted on the uniform back-scatterer was irradiated with He ions with an energy of 100 MeV, which is never recorded as etchable tracks in PADC. It turns out that most of etch pits in the rear surface are made by the back-scattered particles through the investigation of the growth pattern of each etch pit. This method allows simple diagnosis of the ion beam profile and intensity distribution with wide energy range in mixed radiation fields such as laser-driven ion acceleration experiments.

Journal Articles

Behavior of transition into inductively coupled plasma mode with internal radio frequency multiturn antenna

Nakagaki, Keita; Yamauchi, Toshihiko; Kanno, Yoshinori*; Kobayashi, Seiji*; Takemoto, Ryo*

Japanese Journal of Applied Physics, 47(3), p.1745 - 1747, 2008/03

 Times Cited Count:2 Percentile:10.52(Physics, Applied)

The CVD system with internal RF multi-turn antenna coil for 27.12 MHz was developed, and to study the transition between CCP (Capacitively Coupled Plasma) and ICP (Inductively Coupled Plasma). The observed transition was classified into three types of transition: the standard transition, the direct transition without the CCP-mode and the repeated transition. The power boundary condition for each transition which is associated with the gas pressure and RF power is presented. Here, the standard transition was mainly presented: The transition time was 8 $$mu$$s at 10 Pa, which became longer with the increase of gas pressure. The increments of electron temperature and density by the transition into ICP were three times and double figures higher respectively.

Journal Articles

Advanced ceramics synthesized by inductively coupled plasma with inner RF antenna

Nakagaki, Keita; Yamauchi, Toshihiko; Kanno, Yoshinori*; Kobayashi, Seiji*

Japanese Journal of Applied Physics, 47(1), p.797 - 799, 2008/01

 Times Cited Count:1 Percentile:5.5(Physics, Applied)

The CVD system by 27.12 MHz RF heating plasma discharge was developed to investigate the synthesis of the advanced ceramics, particularly diamond. Our system was unique, whose four turns RF antenna coil was installed inside of chamber. Here, we found the interesting physical behavior for the first time which the charge coupled plasma (CCP) changed to the inductively coupled plasma (ICP) suddenly at the threshold power. The plasma characteristics which were measured by the double probe were Te$$sim$$10 eV and ne 10E11 cm$$^{-3}$$ suitable for the dissociation. No impurity was observed in plasma, judging from the spectroscopic measurement. The ball-like diamond was synthesized on the silicon (Si) substrate by the low power RF heating plasma.

Journal Articles

Dissociation characteristics of light absorbed dioxin analogues calculated by density functional theory

Yamauchi, Toshihiko; Kobayashi, Seiji*; Ito, Shinichi*; Yamazaki, Kazuhiko; Kamei, Yasutaka*; Kanno, Yoshinori*

Kankyo Kagakkai-Shi, 19(6), p.507 - 515, 2006/11

Using DFT two benzene rings in Co-PCB are found to be twisted on the bond axis, whose angle is 37.8$$^{circ}$$ in Co-PCB(3,3$$^{'}$$,4,4$$^{'}$$,5), and it is 90$$^{circ}$$ in PCB(1,1$$^{'}$$,2,2$$^{'}$$,3,3$$^{'}$$,4,4$$^{'}$$,5,5$$^{'}$$), and two benzene rings of TCDD or TCDF are in the same plane. Next, the dissociation of chlorine atom from dioxin is realized using the violet light below 318 nm as the bond dissociation energy 3.8$$sim$$3.9 eV estimated by the energy difference between the dioxin and the chlorine atom plus dioxin radical. The orbital bond energy is estimated to be 4.1$$sim$$5.5 eV, and the zero-point energy is also estimated to be 0.38$$sim$$1.65 eV. The bond dissociation energy is inverse proportion to the number of chlorine atoms in dioxins. On the other hand, the dissociation reaction by the extract of chlorine using hydrogen atom is successfully analysed. The reaction times of dechlorination, or the extract reaction of chlorine and the photolytic process, are 22$$sim$$40 fs.

Journal Articles

Plasma diagnostics in JFT-2M

Kasai, Satoshi*; Kamiya, Kensaku; Shinohara, Koji; Kawashima, Hisato; Ogawa, Hiroaki; Uehara, Kazuya; Miura, Yukitoshi; Okano, Fuminori; Suzuki, Sadaaki; Hoshino, Katsumichi; et al.

Fusion Science and Technology, 49(2), p.225 - 240, 2006/02

 Times Cited Count:3 Percentile:25.6(Nuclear Science & Technology)

The diagnostic system of JFT-2M has consisted of about 30 individual diagnostic instruments,which were used to study the plasma production, control, equilibrium, stability, confinement, plasma heating by NBI and/or RF (LH, ICRF, ECH) and current drive by RF. In these instruments, the motional Stark effect (MSE) polarimeter, charge exchanged recombination spectroscopy (CXRS), heavy-ion beam probe (HIBP), time of flight (TOF) neutral particle analyzer, etc. have contributed to make clear the improved mechanism of confinement such as H-mode and High Recycling Steady (HRS) H-mode, and to search the operational region of these modes.The infrared TV camera system and lost ion probe have played a very important role to investigate the heat load onto the walls due to ripple loss particles and escaping ions from core plasma, respectively.

Journal Articles

Measurement of a chirped pulse generation from the ERL-FEL

Iijima, Hokuto; Hajima, Ryoichi; Nagai, Ryoji; Minehara, Eisuke; Yamauchi, Toshihiko

Proceedings of 2nd Annual Meeting of Particle Accelerator Society of Japan and 30th Linear Accelerator Meeting in Japan, p.793 - 795, 2005/07

We report the construction of FEL transport line and the measurement method of chirped FEL pulse. An infrared-chirped pulse is an effective way of dissociating molecules. The chirped FEL pulse oscillator is operated by the JAERI-FEL superconducting accelerator, in which a long pulse of electron beam is produced. Until now, the chirped pulse was measured to be $$Deltaomega/omega_0$$ = 14.3% with the wavelength of 23.3 $$mu$$m and the pulse width of 319 fs at FWHM by an autocorrelation. In order to measure the correlation between time and frequency in the chirped pulse directly, the frequency-resolved optical grating (FROG) is developing. Since the measurement is performed in new experimental room, the vacuum transport line guiding the FEL to the room has been constructed.

Journal Articles

Large-scaled non-thermal laser peeling, cutting and drilling in nuclear decommissioning industry

Minehara, Eisuke; Hajima, Ryoichi; Sawamura, Masaru; Nagai, Ryoji; Kikuzawa, Nobuhiro; Nishimori, Nobuyuki; Iijima, Hokuto; Nishitani, Tomohiro; Kimura, Hideaki*; Oguri, Daiichiro*; et al.

Proceedings of 13th International Conference on Nuclear Engineering (ICONE-13) (CD-ROM), 10 Pages, 2005/05

The JAERI FEL has recently discovered the new FEL lasing of 255fs ultra fast pulse, 6-9% high-efficiency, one gigawatt high peak power, a few kilowatts average power, and wide tunability of medium and far infrared wavelength regions at the same time. Using the new lasing and energy-recovery linac technology, we could extend a more powerful and more efficient free-electron laser (FEL) than 10kW and 25%, respectively, for nuclear industry, pharmacy, medical, defense, shipbuilding, semiconductor industry, chemical industries, environmental sciences, space-debris, power beaming and so on. In order to realize such a tunable, highly-efficient, high average power, high peak power and ultra-short pulse FEL, we need the efficient and powerful FEL driven by the JAERI compact, stand-alone and zero boil-off super-conducting RF linac with an energy-recovery geometry. Our discussions on the FEL will cover the application of non-thermal peeling, cutting, and drilling to decommission the nuclear power plants, and to prevent stress-corrosion cracking in nuclear industry and roadmap for the industrial FELs, the JAERI compact, stand-alone and zero-boil-off cryostat concept and operational experience, the new, highly-efficient, high-power, and ultra fast pulse lasing mode, and the energy-recovery geometry.

Journal Articles

JAERI 10kW high power ERL-FEL and its applications in nuclear energy industries

Minehara, Eisuke; Hajima, Ryoichi; Iijima, Hokuto; Kikuzawa, Nobuhiro; Nagai, Ryoji; Nishimori, Nobuyuki; Nishitani, Tomohiro; Sawamura, Masaru; Yamauchi, Toshihiko

Proceedings of 27th International Free Electron Laser Conference (FEL 2005) (CD-ROM), p.305 - 308, 2005/00

The JAERI high power ERL-FEL has been extended to the more powerful and efficient free-electron laser (FEL) than 10kW for nuclear energy industries, and other heavy industries like defense, shipbuilding, chemical industries, environmental sciences, space-debris, and power beaming and so on. In order to realize such a tunable, highly-efficient, high average power, high peak power and ultra-short pulse FEL, we need the efficient and powerful FEL driven by the JAERI compact, stand-alone and zero boil-off super-conducting RF linac with an energy-recovery geometry. Our discussions on the ERL-FEL will cover the current status of the 10kW upgrading and its applications of non-thermal peeling, cutting, and drilling to decommission the nuclear power plants, and to demonstrate successfully the proof of principle prevention of cold-worked stress-corrosion cracking failures in nuclear power reactors under routine operation using small cubic low-Carbon stainless steel samples.

Journal Articles

Laser pattern profile emitted through optical glass fiber bundle with load

Yamauchi, Toshihiko

Japanese Journal of Applied Physics, 43(9A), p.6473 - 6474, 2004/09

 Times Cited Count:0 Percentile:0(Physics, Applied)

The output pattern of He-Ne laser that passes through the optical glass fiber bundle used for free electron laser etc. depends on the weight of load (modulation of transverse mode). The increment of pattern radius exponentially increases with the load. It is considered that the micro bending causes this increment. Next, the estimated delay time also exponentially increases with the weight of load, and the estimated delay time is the extent of pico-second.

Journal Articles

Neutron capture cross section to $$^{186}$$Re isomeric state

Hayakawa, Takehito; Shizuma, Toshiyuki; Yamauchi, Toshihiko; Minehara, Eisuke; Arisawa, Takashi

Nuclear Physics A, 718, p.665c - 667c, 2003/05

no abstracts in English

Journal Articles

Second harmonic generation in Te crystal using free electron laser

Yamauchi, Toshihiko; Kikuzawa, Nobuhiro; Minehara, Eisuke

Japanese Journal of Applied Physics, Part 1, 41(11A), p.6360 - 6363, 2002/11

 Times Cited Count:2 Percentile:11.17(Physics, Applied)

no abstracts in English

Journal Articles

Improved confinement of neon plasma inside a high-$$T_{c}$$ superconducting tube

Yamauchi, Toshihiko; Matsuzawa, Hidenori*; Mikami, Koji*; Ishikawa, Junichi*

Japanese Journal of Applied Physics, Part 1, 41(9), p.5799 - 5800, 2002/09

 Times Cited Count:3 Percentile:16.19(Physics, Applied)

This paper describes the experimental result of the interaction between a high-Tc superconductor and charged particles (plasma). This study is expected for the interaction between the charged particle and superconductor in the group, high-Tc superconducting wiggler for electron beam of FEL (collaboration with Prof.Matsuzawa) and high-Tc superconducting tube for beam guiding published in the journal "Nature".

JAEA Reports

Proceedings of the Workshop on Applications of IRFEL and Nuclear Isomers; Septemper 28, 2001, JAERI, Tokai, Japan

Yamauchi, Toshihiko; Hayakawa, Takehito; Shizuma, Toshiyuki

JAERI-Conf 2002-007, 54 Pages, 2002/08

JAERI-Conf-2002-007.pdf:5.32MB

The workshop on application of free-electron laser (FEL) and nuclear isomer study was held at Tokai Research Establishment of JAERI on September 28. The workshop was devoted to the discussions and the presentations of two thema as follows: Six papers associated with the laser compton gamma-ray, the photonuclear physics and the nuclear astrophysics using the gannma-ray produced by the T3 laser were presented in the morning session. Seven papers including an invited talk on the behavior of molecules in intense laser light fields and associated with the chemical decomposition of dioxin, the silicon isotope separetion, the infrared photoexcitation spectroscopy, the laser-tissue interaction and the single-wall carbon nanotube and nanohorn by FEL etc. were also presented in the afternoon session. The intensive discussion was exchanged among approximately 50 participants. Each performance during the first workshop was fully telecomunicated by a video conference system between Tokai and Kizu (Kansai Research Establishment) sites.

Journal Articles

Recent progress and future plans of the JAERI superconducting rf linac-based FEL facility

Minehara, Eisuke; Yamauchi, Toshihiko; Sugimoto, Masayoshi; Sawamura, Masaru; Hajima, Ryoichi; Nagai, Ryoji; Kikuzawa, Nobuhiro; Nishimori, Nobuyuki; Shizuma, Toshiyuki

Proceedings of 27th Linear Accelerator Meeting in Japan, p.21 - 23, 2002/08

The JAERI superconducting rf linac-based free-electron laser(FEL) has been modified to recover the beam energy after the lasing utilizing a 360 degree recirculating loop and other components. Recent progress on the energy recovery experiments and future plans of the JAERI superconducting rf linac-based FELs will be reported and discussed briefly.

Journal Articles

A study on decomposition of dioxins analogues by IR laser irradiation

Yamauchi, Toshihiko

Kankyo Kagakkai-Shi, 14(6), p.567 - 575, 2001/12

no abstracts in English

Journal Articles

Demonstration of the highly-efficient and high-power FELs driven by a superconducting rf linac

Minehara, Eisuke; Hajima, Ryoichi; Sawamura, Masaru; Nagai, Ryoji; Nishimori, Nobuyuki; Kikuzawa, Nobuhiro; Sugimoto, Masayoshi; Yamauchi, Toshihiko; Hayakawa, Takehito; Shizuma, Toshiyuki

Proceedings of 13th Symposium on Accelerator Science and Technology, p.150 - 154, 2001/10

We need a powerful and efficient free-electron laser(FEL) for industrial uses, for examples, pharmacy, medical, defense, shipbuilding, semiconductor industry, chemical industries, environmental sciences, space-debris, power beaming and so on. In order to realize such a tunable, highly-efficient, high average power, high peak power and ultra-short pulse FEL, the JAERI FEL group and I have successfully demonstrated the efficient and powerful FEL driven by a compact, stand-alone and zero-boil-off super-conducting rf linac with an energy-recovery geometry. Our discussions on the FEL will cover market-requirements for the industrial FELs, some answers from the JAERI compact, stand-alone and zero-boil-off cryostat concept and operational experience over these 8 years, our discovery of the new, highly-efficient, high-power, and ultra-short pulse lasing mode, and the energy-recovery geometry.

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