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Sakai, H.

 
Paper Title Page
TUPCH132 Higher Order Mode (HOM) Damper of 500 MHz Damped Cavity for ASP Storage Ring 1325
 
  • J. Watanabe, K. Nakayama, K. Sato, H. Suzuki
    Toshiba, Yokohama
  • M. Izawa
    KEK, Ibaraki
  • A. Jackson, G. LeBlanc, K. Zingre
    ASP, Clayton, Victoria
  • T. Koseki
    RIKEN/RARF/CC, Saitama
  • N. Nakamura, H. Sakai, H. Takaki
    ISSP/SRL, Chiba
 
  TOSHIBA has delivered the storage ring RF system for the Australian Synchrotron Project(ASP). Two pairs of the 500MHz Higher Order Mode(HOM) damped cavities were applied for this system. Two on-centered and one off-centered dampers were attached for damping the longitudinal HOM impedance down to less than 20kOhm/GHz. In order to reduce the coupling of off-center damper for accelerating mode and improve cooling power of damper, New HOM damper was designed by optimizing SiC absorber structure and damper antenna length using HFSS code. The design and manufacture of the new HOM damper and the test are described.  
WEPCH025 COD Correction at the PF Ring by New Orbit Feedback Scheme 1978
 
  • K. Harada, T. Obina
    KEK, Ibaraki
  • N. Nakamura, H. Sakai, H. Takaki
    ISSP/SRL, Chiba
 
  When we correct the global COD (closed orbit distortion), if we use the modified conversion matrix calculated by the eigen vector method with constraint conditions (EVC), the local orbit correction can be simultaneously done to fix the light source point in the insertion device. In the EVC, the local orbit correction is combined to the global orbit correction by the Lagrange's undetermined multiple method. In this paper, we show the machine study results at the PF Ring.  
THOBFI02 Measurement of the Beam Profiles with the Improved Fresnel Zone Plate Monitor 2784
 
  • H. Sakai, N. Nakamura
    ISSP/SRL, Chiba
  • H. Hayano, T. Muto
    KEK, Ibaraki
 
  We present the recent progress of the FZP (Fresnel Zone Plate) beam profile monitor constructed at KEK-ATF damping ring. This monitor based on an X-ray imaging optics with two FZPs*. In this monitor, the transverse electron beam image at bending magnet is twenty-times magnified by the two FZPs and detected on an X-ray CCD camera. Then the real-time and 2-dimentional transverse beam profiles can be obtained with non-destructive manner by using this monitor. The expected spatial resolution is less than 1 micro-meter. Recently, we install the new mechanical shutter to improve time resolution of the monitor and avoid the effects of the short-term movement of the beam or the monitor itself. By applying this shutter, the shutter opening time was reduced less than 1ms and the beam profile could be measured more accurately. In this paper, we report the new shutter performance and the measurement results of beam profiles by the improved FZP beam profile monitor.

*K. Iida, et al. Nucl. Instrum. Meth. A 506 (2003) 41-49.

 
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TUPCH126 Outgassing Rate of Highly Pure Copper Electroplating Applied to RF Cavities 1307
 
  • T. Abe, T. Kageyama, Y. Saito, H. Sakai, Y. Sato, Y. Takeuchi
    KEK, Ibaraki
  • Z. Kabeya, T. Kawasumi
    MHI, Nagoya
  • T. Nakamura, S. Nishihashi, K. Tsujimoto
    Asahi Kinzoku Co., Ltd., Gifu
  • K. Tajiri
    Churyo Engineering Co., Ltd., Nagoya
 
  We plan to apply a new copper electroplating with a high purity and a high electric conductivity to normal-conducting RF cavities for electron or positron storage rings with a high current beam. As reported in 2005 Particle Accelerator Conference, our first test cavity, made of iron, with the electroplated copper surface finished up by electropolishing showed an excellent electric performance compared with the case of cavities made of oxygen free copper. Our next step is to examine the vacuum performance. This paper reports results of the outgassing-rate measurements on our second test cavity together with its fabrication process.  
TUPCH127 Fine Grooving of Conductor Surfaces of RF Input Coupler to Suppress Multipactoring 1310
 
  • T. Abe, T. Kageyama, H. Sakai, Y. Takeuchi
    KEK, Ibaraki
 
  An RF input coupler to feed high power into an accelerating cavity with heavy beam loading undergoes many multipactoring zones due to the wide range of the input RF power. Furthermore, a regular coaxial line is more subject to multipactoring than a rectangular waveguide because of the uniformity of the electromagnetic field. Grooving the conductor surfaces of the coaxial line is a promising method to suppress multipactoring under any conditions expected in the above cases. This paper reports results of our multipactoring simulation study and the high power test of the input coupler with a grooved coaxial line.  
THPCH154 Development of Pulsed Laser Super-cavity for Compact High Flux X-ray Sources 3155
 
  • K. Sakaue, M. Washio
    RISE, Tokyo
  • S. Araki, Y. Higashi, Y. Honda, T. Taniguchi, J. Urakawa
    KEK, Ibaraki
  • M.K. Fukuda, M. Takano
    NIRS, Chiba-shi
  • H. Sakai
    ISSP/SRL, Chiba
  • N. Sasao
    Kyoto University, Kyoto
 
  Pulsed-laser super-cavity is being developed at KEK-ATF for the application of a compact high brightness x-ray source based on Laser Compton Scattering. We use a Fabry-Perot optical cavity with a pulsed laser. The cavity increases a laser effective power, and at the same time, stably makes a small laser spot in side the cavity. In addition, the pulsed-laser gives much higher peak power. Thus, this scheme will open up a new possibility for building a compact high-brightness x-ray source, when collided with an intense bunched electron beam. We are now planning to build such an x-ray source with a 50MeV multi-bunch linac and a 42cm Fabry-Perot cavity using pulse stacking technology. We actually finished construction of the 50MeV linac and will start its operation in the spring, 2006. Development of the pulsed-laser super-cavity and future plan of our compact x-ray source will be presented at the conference.