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Kitamura, H.

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MOPC018 Seeding the FEL of the SCSS Test Accelerator with the 5th Harmonic of a Ti: Sa Laser Produced in Gases 109
 
  • G. Lambert, O. V. Chubar, M.-E. Couprie
    SOLEIL, Gif-sur-Yvette
  • M. Bougeard, B. Carré, D. Garzella, O. B. Gobert, M. Labat, H. Merdji, P. Salieres
    CEA, Gif-sur-Yvette
  • T. Hara, T. Ishikawa, H. Kitamura, T. Shintake, M. Yabashi
    RIKEN/SPring-8, Hyogo
  • K. Tahara, Y. T. Tanaka, T. Tanikawa
    RIKEN Spring-8 Harima, Hyogo
 
  We present the strong amplification of the 5th harmonic of a Ti: Sa laser (10 Hz, 100 fs) generated in a Xe gas cell, i.e. 160 nm, and the generation of intense and coherent odd and even Non Linear Harmonics (NLH) from 80 nm to 23 nm. The experiment has been carried out on the SCSS (SPring-8 Compact SASE Source, Japan) Test Accelerator FEL. This facility is mainly based on a thermionic cathode electron gun, a C-band LINAC (5712 MHz, 35 MV/m) and an in-vacuum undulator (15 mm of period, 2 sections of 4.5 m length). The external source is properly focused in the first undulator section in order to efficiently interact with the electron beam (150 MeV, 10 Hz, 0.5-3 ps). In case of high peak current mode, the 160 nm seed light is amplified by a factor of 7000 in the first undulator section. Moreover, the amplification can be observed even for very low HHG seed level. This result opens new perspectives for seeding at short wavelengths in the XUV to soft X-Ray region. Association with NLH, HGHG (High Gain Harmonic Generation) and/or cascade schemes would allow the generation of fully coherent X-ray radiations from the “water window” spectral range to the Angstrom region.  
TUPC054 Pulse-by-pulse Photon Beam Monitor with Microstripline Structure in NSRRC 1176
 
  • C. K. Kuan, C. L. Chen, J.-R. Chen, G.-Y. Hsiung, I. C. Sheng, Z.-D. Tsai, D.-J. Wang
    NSRRC, Hsinchu
  • H. Aoyagi, H. Kitamura, S. Takahashi
    JASRI/SPring-8, Hyogo-ken
 
  In order to diagnostic pulse-by-pulse beam movement of photon beam, NSRRC(Taiwan) and SPring-8 (Japan) have worked together to develop a front end beam monitor with microstripline structure, which is designed to have specific impedance of 50 ohm. The detector head is composed of a metal line (copper), ceramic plates (aluminum nitride) and a cooling base (copper tungsten). The metal line functions as a photocathode. The metal line is directly connected to SMA feed-through connectors to have fast response time. The detector head has been fabricated in SPring-8, and mounted on the monitor chamber and installed in NSRRC Superconducting Wiggler (SW) front end. The beam monitor can be used to examine not only pulse-by-pulse photon beam, but also the storage ring intensity and the pulse timing. Unique feature of the monitor is to produce unipolar short pulses. The design, fabrication and the measurement will be presented in this paper.  
WEOAM01 Operation Status of the SCSS Test Accelerator: Continuous Saturation of SASE FEL at the Wavelength Range from ~50 to 60 nanometers 1944
 
  • H. Tanaka, T. Fukui, T. Hara, A. Higashiya, N. Hosoda, T. Inagaki, S. I. Inoue, T. Ishikawa, H. Kitamura, M. K. Kitamura, H. Maesaka, M. Nagasono, T. Ohshima, Y. Otake, T. Sakurai, T. Shintake, K. Shirasawa, T. Tanaka, K. Togawa, M. Yabashi
    RIKEN/SPring-8, Hyogo
  • T. Asaka, T. Hasegawa, H. Ohashi, S. Takahashi, S. Tanaka
    JASRI/SPring-8, Hyogo-ken
  • T. Tanikawa
    RIKEN Spring-8 Harima, Hyogo
 
  The SPring-8 compact SASE source (SCSS) test accelerator for XFEL/SPring-8 was constructed in 2005. The first lasing at 49 nm, though not reached saturation, was observed with the 250-MeV electron beam in June 2006. Towards the saturation, we started stabilizing the RF system in the injector section, which dramatically stabilized the lasing condition. The stable operation enables us to tune each of the machine parameter precisely by using the lasing response. The second undulator, which did not sufficiently contribute to the first lasing because of large multipole field errors, was replaced by new one. These improvements led us to the successful observation of SASE saturation at the wavelength ranging from ~50 to 60 nm in September 2007. A pulse-energy of 30 uJ is routinely obtained at 60 nm. Analysis of the obtained SASE saturation data with a 3D-FEL simulation code, SIMPLEX, suggests that the electron beam emittance is almost unchanged through the bunch compression process. The stable and intense EUV SASE FEL has been offered for user experiments since October 2007. The achieved electron beam performance, lasing property as well as the latest analysis result will be presented.  
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THPC146 Beam Halo Monitor Using Diamond Detectors for XFEL/SPring-8 3330
 
  • H. Aoyagi, Y. Asano, T. Bizen, K. Fukami, N. Nariyama
    JASRI/SPring-8, Hyogo-ken
  • T. Itoga, H. Kitamura, T. Tanaka
    RIKEN/SPring-8, Hyogo
 
  The construction of the XFEL facility at SPring-8 has been started. We have been developing a halo monitor as an interlock device for protection of undulator permanent magnets against radiation damage. When permanent magnets are irradiated with a halo part of 8GeV electron beam, magnetic fields are degraded permanently and laser oscillation is weakened. Therefore, the interlock device is required during machine operation. Diamond detector, which operates in photoconductive mode, is good candidate for electron beam sensor. The beam test of the diamond detector head has been carried out at the beam dump of the SPring-8 booster synchrotron. Minimum number of injected electron was about 1·105 /pulse, and we observed the pulse height of 0.1V having the pulse length of 0.6nsec FWHM without a preamplifier. The linearity of output signal on injected beam was also demonstrated. The beam halo monitor equipped with the diamond detectors is under manufacturing. The design and feasibility tests will be presented in this conference.