Author: Hayano, H.
Paper Title Page
  • T. Naito, S. Araki, H. Hayano, K. Kubo, S. Kuroda, T. Okugi, N. Terunuma, J. Urakawa
    KEK, Ibaraki, Japan
  In order to observe the motion of bunch-by-bunch beam oscillation of multi-bunch in the storage ring, we developed two measurement tools. One is a signal process electronics circuit using fast analogue switches. The circuit picks up one of the selected bunch signal of the beam position monitor from the multi-bunch. The selected beam position signal can be processed as a single bunch beam. By changing the gate timing, arbitrary bunch signal can be selected. The other is a waveform memory using a high bandwidth oscilloscope. The long waveform memory of the oscilloscope has a capability to acquire the multi-turn waveform of the button electrode signals. The beam test of the circuit has been carried out at KEK-ATF damping ring in the cases of 2.8ns bunch spacing and 5.6ns bunch spacing, respectively. The detail of the hardware and the result of the beam test are reported.  
MOPME019 Alignment Detection Study using Beam Induced HOM at STF 509
  • A. Kuramoto
    Sokendai, Ibaraki, Japan
  • H. Hayano
    KEK, Ibaraki, Japan
  STF accelerator using L-band photocathode RF Gun and two superconducting cavities is under operation for R&D of ILC. Electron beam extracted from the RF Gun is accelerated to 40 MeV by two superconducting cavities. Cavity alignment requirements for ILC are less than 300um offset and 300urad tilt with respect to cryomodule. It is necessary to measure their offset and tilt inside of cryomodule. Cavity offset has been already measured by using beam induced HOM at FLASH in DESY. Cavity deformation during assembly and by cooling contraction has not been examined yet. We measured HOM signals to detect their tilt and bending. TE111-6 which has high impedance is used to estimate cavity offset. To find cavity tilt and bending, we selected pi over nine mode in the first dipole passband (TE111-1) and beam pipe modes. From information of TE111-1 which has maximum radial electric field in the middle cell, we can get electrical center of middle cell. At beam pipes, electrical center can be found by using beam pipe modes. Combinations of these electrical centers tell us cavity tilt and bending. We will present results of these TE111-1 and beam pipe mode together with beam trajectory information.  
WEPWO015 Electron Beam Welding for High Gradient Superconducting Cavity 2346
  • T. Kubo, Y. Ajima, H. Hayano, H. Inoue, S. Kato, T. Saeki, M. Sawabe, K. Umemori, Y. Watanabe, S. Yamaguchi, M. Yamanaka
    KEK, Ibaraki, Japan
  • Y. Iwashita
    Kyoto ICR, Uji, Kyoto, Japan
  • T. Nagata
    ULVAC, Inc., Tsukuba, Japan
  Relations between electron beam welding parameters and appearances of weld beads are studied. It was found that a beam generator position and a welding direction affect a geometry of weld bead dramatically. Carbon including contaminants found after the chemistry are also commented.  
WEPWO017 Efforts on Nondestructive Inspections for SC Cavities 2352
  • Y. Iwashita, Y. Fuwa, M. Hashida, S. Sakabe, S. Tokita, H. Tongu
    Kyoto ICR, Uji, Kyoto, Japan
  • H. Hayano, K. Watanabe, Y. Yamamoto
    KEK, Ibaraki, Japan
  • K. Otani
    INRS-EMT, Varennes (Québec), Canada
  The high resolution camera, so-called Kyoto Camera, inspecting the Sc cavity inner surface showed the importance of nondestructive inspections to improve yield in production of high performance SC Cavities. Further efforts have been continued for the inspection and the high resolution T-map, X-map and eddy current scanner have been developed. A radiography to detect small voids inside the Nb EBW seam with the target resolution of 0.1 mm is under investigation. We have carried out radiography tests with X-rays induced from an ultra short pulse intense laser.  
WEPME013 Development and Test of a Fully Automated PkQl Control Procedure at KEK STF 2950
  • M. Omet, A. Kuramoto
    Sokendai, Ibaraki, Japan
  • H. Hayano, T. Matsumoto, S. Michizono
    KEK, Ibaraki, Japan
  In order to operate the cavities near their maximum gradients, cavity input (Pk) and cavity loaded Q (QL) should be controlled individually (PkQL control) at the International Linear Collider (ILC). A manual PkQL operation procedure was developed and performed at the linear electron accelerator at the Superconducting RF Test Facility (STF), in which the beam is accelerated up to 40 MeV by two superconducting 9-cell TESLA type L band cavities. The cavity gradients were set to 16 MV/m and 24 MV/m with QL values of 1106 and 3·106. A 6.2 mA beam with a pulse length of 154 us was used. The field stabilities in amplitude were 0.160% and 0.097% for the cavities and 0.016% for the vector sum. The stabilities without beam are 0.057% and 0.054% for the cavities and 0.009% for the vector sum. For stability improvement during beam transient an adaptive beam feedforward for beam loading compensation is under development. So far an amplitude field stability of 0.013% for the vector sum was achieved at cavity gradients of 15 MV/m and 25 MV/m (no PkQL control) during a 6.8 mA beam with a pulse length of 123 us. Furthermore a fully automated PkQL control procedure is currently developed and tested.  
poster icon Poster WEPME013 [0.647 MB]  
THOBB203 Study on Fabrication of Superconducting RF 9-cell Cavity for ILC at KEK 3132
  • T. Saeki, Y. Ajima, K. Enami, H. Hayano, H. Inoue, E. Kako, S. Kato, S. Koike, T. Kubo, S. Noguchi, M. Satoh, M. Sawabe, T. Shishido, A. Terashima, N. Toge, K. Ueno, K. Umemori, K. Watanabe, Y. Watanabe, S. Yamaguchi, A. Yamamoto, Y. Yamamoto, M. Yamanaka, K. Yokoya
    KEK, Ibaraki, Japan
  • Y. Iwashita
    Kyoto ICR, Uji, Kyoto, Japan
  • N. Kawabata, H. Nakamura, K. Nohara, M. Shinohara
    SPS, Funabashi-shi, Japan
  • F. Yasuda
    The University of Tokyo, Institute of Physics, Tokyo, Japan
  We constructed a new facility for the fabrication of superconducting RF cavity at KEK from 2009 to 2011. In the facility, we have installed a deep-drawing machine, a half-cell trimming machine, an electron-beam welding machine, and a chemical etching room in one place. We started the study on the fabrication of 9-cell cavity for International Linear Collier (ILC) from 2009 using this facility. The study is focusing on the cost reduction with keeping high performance of cavity, and the goal is the establishment of mass-production procedure for ILC. This article reports the current status of the studies in CFF.  
slides icon Slides THOBB203 [3.983 MB]