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Katoh, M.

Paper Title Page
WEPEA039 Status of Top-up Operation in UVSOR-II 2576
 
  • H. Zen, K. Hayashi, J. Yamazaki
    UVSOR, Okazaki
  • M. Adachi, M. Katoh, T. Tanikawa, H. Zen
    Sokendai - Okazaki, Okazaki, Aichi
  • M. Hosaka, Y. Taira, N. Yamamoto
    Nagoya University, Nagoya
 
 

UVSOR-II is a low emittance, 750 MeV synchrotron light source. Low emittance and low energy synchrotron light sources naturally suffered from short electron lifetime due to Touschek effect. Top-up operation is a solution for overcoming the effect. In the UVSOR-II, trials of multi-bunch top-up operation at the full energy were started from 2008. In the trials, we have succeeded in keeping the stored beam current around 300 mA for 12 hours. From this fiscal year, single bunch injection was started for single bunch user operations and for experiments on advanced light source development such as Free Electron Laser (FEL), Coherent Synchrotron Radiation (CSR), Coherent Harmonic Generation (CHG), which require single bunch or 2-bunch filling operation. We have already performed single bunch top-up operation in user time with the stored beam current of 50 mA. And FEL lasing with top-up operation was also achieved at the laser wavelength of 215 nm with the stored beam current of 130 mA / 2-bunch. In the FEL lasing experiment, we succeeded in keeping the average power of FEL around 130 mW for three hours.

 
MOPE016 Beam Monitor System for Central Japan Synchrotron Radiation Research Facility 993
 
  • M. Hosaka, Y. Furui, H. Morimoto, A. Nagatani, K. Takami, Y. Takashima, N. Yamamoto
    Nagoya University, Nagoya
  • M. Adachi, M. Katoh, H. Zen
    UVSOR, Okazaki
  • T. Tanikawa
    Sokendai - Okazaki, Okazaki, Aichi
 
 

Central Japan Synchrotron Radiation Research Facility which provides synchrotron radiation for a large community of users is under construction in the Aichi prefecture, Japan. The light source accelerator complex consists of a linac, a booster synchrotron and a storage ring. We have developed beam monitor systems which play important role especially in the commissioning stage of the accelerators. An RF knockout system to observe betatron tune of the electron beam in the booster synchrotron and the storage ring has been designed. We paid special attention in an RF source fed to a shaker to realize efficient measurement of the tune of electron beam during acceleration. We made a test experiment using electron beam of a booster synchrotron of the UVSOR facility. We have also developed a BPM system which enables a single path beam monitoring. The signal processing is based on a fast digital oscilloscope and a simple preprocessor circuit which was developed to improve position resolution. The performance was evaluated using an injection beam pulse to the storage ring of the UVSOR.

 
TUPD091 Generation of Ultra-Short Gamma-ray Pulses by Laser Compton Scattering in an Electron Storage Ring 2117
 
  • Y. Taira, M. Hosaka, K. Soda, Y. Takashima, N. Yamamoto
    Nagoya University, Nagoya
  • M. Adachi, M. Katoh, H. Zen
    UVSOR, Okazaki
  • T. Tanikawa
    Sokendai - Okazaki, Okazaki, Aichi
 
 

We are developing an ultra-short gamma ray pulse source based on laser Compton scattering technology at the 750 MeV electron storage ring UVSOR-II. Ultra-short gamma ray pulses can be generated by injecting femtosecond laser pulses into the electron beam circulating in an electron storage ring from the direction perpendicular to the orbital plane. The energy, intensity, and pulse width of the gamma rays have been estimated to be 6.6 MeV, 2.4× 106 photons s-1, and 150 fs, respectively, for the case of UVSOR-II with a commercially available femtosecond laser. These parameters can be tuned by changing the incident angle of the laser to the electron beam, electron energy, and the size of the laser. A preliminary head-on collision experiment was carried out. The measured spectral shape agreed well with simulation including the detector response calculated by the EGS5 code*, which implied the generation of gamma rays by laser Compton scattering and the validity of the estimation of the gamma ray intensity in the case of 90-degree collisions.


* H. Hirayama et al., SLAC-R-730, (2005).

 
TUPE029 Spectral Measurement of VUV CHG at UVSOR-II 2206
 
  • T. Tanikawa
    Sokendai - Okazaki, Okazaki, Aichi
  • M. Adachi, M. Katoh, J. Yamazaki, H. Zen
    UVSOR, Okazaki
  • M. Hosaka, Y. Taira, N. Yamamoto
    Nagoya University, Nagoya
 
 

Light source technologies based on laser seeding are under development at the UVSOR-II electron storage ring. In the past experiments, we have succeeded in generating coherent DUV (Deep Ultra-Violet) harmonics with various polarizations. A spectrum measurement experiment of CHG (Coherent Harmonic Generation) was carried out by using a spectrometer of from visible to DUV range. In order to diagnose spectra of shorter-wavelength CHG, a spectrometer for VUV (Vacuum Ultra-Violet) has been constructed and the VUV CHG was measured. In addition, we try to use a seeding light source based on not only fundamental of Ti: Sapphire laser and the harmonics generated from non-linear crystals but also HHG (High Harmonic Generation) in a gas for the CHG experiment. Now the HHG system is under development. In this presentation, we introduce the VUV spectral measurement system and the HHG system and also report about comparison between the results of the current CHG experiments and design studies of numerical calculation for them.

 
WEPEA036 Accelerators of the Central Japan Synchrotron Radiation Research Facility Project 2567
 
  • N. Yamamoto, M. Hosaka, H. Morimoto, K. Takami, Y. Takashima
    Nagoya University, Nagoya
  • Y. Hori
    KEK, Ibaraki
  • M. Katoh
    UVSOR, Okazaki
  • S. Koda
    SAGA, Tosu
  • S. Sasaki
    JASRI/SPring-8, Hyogo-ken
 
 

Central Japan Synchrotron Radiation (SR) Research Facility is under construction in the Aichi area, and the service will start from FY2012. Aichi Science & Technology Foundation is responsible for the operation and management, and Nagoya University SR Research Center is responsible to run the facility and support the users technically and scientifically. The accelerators consists of an injector linac, a booster synchrotron and an 1.2 GeV electron storage ring with the circumference of 72 m. To save construction expenses, the 50 MeV linac and the booster with the circumference of 48 m are built at inside of the storage ring. The beam current and natural emittance of the storage ring are 300 mA and 53 nmrad. The magnetic lattice consists of four triple bend cells and four straight sections 4 m long. The bending magnets at the centers of the cells are 5 T superbends and the critical energy of the SR is 4.8 keV. More than ten hard X-ray beam-line can be constructed. One variable polarization undulator will be installed in the first phase. The electron beam will be injected from the booster with the full energy and the top-up operation will be introduced as early as possible.

 
WEPEA037 Study of the Coherent Terahertz Radiation by Laser Bunch Slicing at UVSOR-II Electron Storage Ring 2570
 
  • N. Yamamoto, M. Hosaka, Y. Taira, Y. Takashima
    Nagoya University, Nagoya
  • M. Adachi, M. Katoh, S.I. Kimura, H. Zen
    UVSOR, Okazaki
  • M. Shimada
    KEK, Ibaraki
  • T. Takahashi
    KURRI, Osaka
  • T. Tanikawa
    Sokendai - Okazaki, Okazaki, Aichi
 
 

Terahertz (THz) coherent synchrotron radiation (CSR) is emitted not only from shorter electron bunches compared with the radiation wavelength but also from electron bunches withμstructures. Formation ofμstructures at sub picosecond scale in electron bunches by a laser slicing technique is experimentally studied through observation of THz CSR. The properties of the THz CSR such as intensity or spectrum depend strongly on the shape and amplitude of theμstructure created in the electron bunches. To study in detail the formation ofμstructure in electron bunches using the laser slicing technique, we have performed experiments at the UVSOR-II electron storage ring. THz CSR, which contains information on theμstructure, was observed under various laser conditions. The THz CSR spectrum was found to depend strongly on the intensity and the pulse width of the laser. The results agreed qualitatively with a numerical calculation. It was suggested that the evolution of theμstructure during CSR emission is important under some experimental conditions.

 
WEPEA038 Present Status and Upgrade Plan on Coherent Light Source Developments at UVSOR-II 2573
 
  • M. Adachi, K. Hayashi, M. Katoh, S.I. Kimura, J. Yamazaki, H. Zen
    UVSOR, Okazaki
  • M. Hosaka, Y. Taira, Y. Takashima, N. Yamamoto
    Nagoya University, Nagoya
  • T. Takahashi
    KURRI, Osaka
  • T. Tanikawa
    Sokendai - Okazaki, Okazaki, Aichi
 
 

UVSOR, a 750 MeV synchrotron light source of 53m circumference had been operated for more than 20 years. After a major upgrade in 2003, this machine was renamed to UVSOR-II. The ring is now routinely operated with low emittance of 27 nm-rad and with four undulators. By utilizing a part of the existing FEL system and an ultra-short laser system, coherent synchrotron radiation in THz range and coherent harmonic generation in VUV range have been extensively studied under international collaborations. Based on results obtained from previous coherent light source developments, a new five-year research program on the coherent light source developments has been started from FY2008, which includes creation of a new 4-m long straight section by moving the injection point, upgrades of the undulator and the laser system and construction of dedicated beam-lines for these coherent light sources. Present status and upgrade plan on these coherent light sources at UVSOR-II will be presented at the conference.

 
TUPE091 Recent Progress in the Energy Recovery Linac Project in Japan 2338
 
  • S. Sakanaka, M. Akemoto, T. Aoto, D.A. Arakawa, S. Asaoka, A. Enomoto, S. Fukuda, K. Furukawa, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, H. Honma, T. Honma, K. Hosoyama, M. Isawa, E. Kako, T. Kasuga, H. Katagiri, H. Kawata, Y. Kobayashi, Y. Kojima, T. Matsumoto, H. Matsushita, S. Michizono, T.M. Mitsuhashi, T. Miura, T. Miyajima, H. Miyauchi, S. Nagahashi, H. Nakai, H. Nakajima, E. Nakamura, K. Nakanishi, K. Nakao, T. Nogami, S. Noguchi, S. Nozawa, T. Obina, S. Ohsawa, T. Ozaki, C.O. Pak, H. Sakai, H. Sasaki, Y. Sato, K. Satoh, M. Satoh, T. Shidara, M. Shimada, T. Shioya, T. Shishido, T. Suwada, M. Tadano, T. Takahashi, R. Takai, T. Takenaka, Y. Tanimoto, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, K. Watanabe, M. Yamamoto, S. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida
    KEK, Ibaraki
  • M. Adachi, M. Katoh, H. Zen
    UVSOR, Okazaki
  • R. Hajima, R. Nagai, N. Nishimori, M. Sawamura
    JAEA/ERL, Ibaraki
  • H. Hanaki
    JASRI/SPring-8, Hyogo-ken
  • H. Iijima, M. Kuriki
    HU/AdSM, Higashi-Hiroshima
  • I. Ito, H. Kudoh, N. Nakamura, S. Shibuya, K. Shinoe, H. Takaki
    ISSP/SRL, Chiba
  • H. Kurisu
    Yamaguchi University, Ube-Shi
  • M. Kuwahara, T. Nakanishi, S. Okumi
    Nagoya University, Nagoya
  • S. Matsuba
    Hiroshima University, Graduate School of Science, Higashi-Hiroshima
  • T. Muto
    Tohoku University, School of Scinece, Sendai
  • K. Torizuka, D. Yoshitomi
    AIST, Tsukuba
 
 

Future synchrotron light source using a 5-GeV-class energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting active R&D efforts for that. We are developing super-brilliant DC photocathode guns, two types of cryomodules for both injector and main superconducting linacs, 1.3 GHz high CW-power rf sources, and other important components. We are also constructing a compact ERL for demonstrating the recirculation of low-emittance, high-current beams using those key components. We present our recent progress in this project.

 
THOBRA03 Observation of Transverse-Longitudinal Coupling Effect at UVSOR-II 3650
 
  • M. Shimada
    KEK, Ibaraki
  • M. Adachi, M. Katoh, S.I. Kimura
    UVSOR, Okazaki
  • M. Hosaka, Y. Takashima, N. Yamamoto
    Nagoya University, Nagoya
  • T. Takahashi
    KURRI, Osaka
  • T. Tanikawa
    Sokendai - Okazaki, Okazaki, Aichi
 
 

It was theoretically predicted that, when the electron pulse length comes into the femto-second range, transverse motion of the electrons is strongly coupled with the longitudinal one and makes significant effect on the pulse shape. In the experiments, a fine dip structure was created on the electron bunches circulating in a storage ring by a so-called laser bunch slicing technique and then the evolution of the structure was measured through the spectrum of the coherent synchrotron radiation. When the ring was operated in a low-alpha mode, the shape of the dip structure was oscillating with the transverse betatron frequency, which clearly indicates the existence of the longitudinal-transverse coupling effect. This understanding will be crucially important for generation and transportation of ultra-short electron bunches in light sources or colliders for high energy physics. In this presentation, the dependency of the CSR signal intensity on the wavelength of the THz CSR and the electron beam current are also reported.

 

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