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Urakawa, J.U.

Paper Title Page
MPPE044 Damping Wiggler Study at KEK-ATF 2809
 
  • T. Naito, H. Hayano, Y. Honda, K. Kubo, M. Kuriki, S. Kuroda, T. Muto, N. Terunuma, J.U. Urakawa
    KEK, Ibaraki
  • M. Korostelev, F. Zimmermann
    CERN, Geneva
  • N. Nakamura, H. Sakai
    ISSP/SRL, Chiba
  • M.C. Ross
    SLAC, Menlo Park, California
 
  The effects by damping wiggler magnets have been studied at KEK-ATF. The damping ring of the KEK-ATF is a 1.3 GeV storage ring capable of producing ultra-low emittance electron beams. It is significant issue to realize fast damping in the damping ring. The tuning method with 4 sets of wiggler was investigated for the ultra-low emittance beam. The performance on the beam quality, which is related to the transverse (x and y) and the longitudinal (z and dp/p), has been measured by the SR monitor, the laser wire, the streak camera and the energy spread monitor at the extraction line. We report on the operation condition and the measurement results.  
TPPE049 Synchronizaiton Between Laser and Electron Beam at Photocathode RF Gun 3079
 
  • A. Sakumi, A. Fukasawa, Y. Muroya, T. Ueda, M. Uesaka, K. Yoshii
    UTNL, Ibaraki
  • K. Dobashi
    NIRS, Chiba-shi
  • N. Kumagai, H. Tomizawa
    JASRI/SPring-8, Hyogo
  • J.U. Urakawa
    KEK, Ibaraki
 
  The chemical reactions of hot, room temperature and critical water in a time-range of picosecond and sub-picosecond have been carried out by the 18 MeV S-band linac and a Mg photocathode RF gun with the irradiation of third harmonic Ti: Sapphire laser, at Nuclear Engineering Research Laboratory (NERL), the University of Tokyo. Although this short bunch and 100 fs laser light are enough to perform the experiment of radiation chemistry in the time-range of sub-picosecond, the total time-resolution become worse by the instability of synchronization between laser and radio frequency of linac. We found that the fluctuation of room temperature causes the instability, particularly the cycle of turning on/off of the air-conditioner. It is shown that 0.3 °C (peak-to-peak) fluctuation of the laser-room temperature have approximately corresponded to the instability of 6 ps. We are trying to decrease the fluctuation of the room temperature, together with the local temperature stability of the Ti: Sapphire crystal, the pumping laser. Furthermore, we will develop the feed back system for reducing the instability of the synchronization.  
TOPE003 Results from DR and Instrumentation Test Facilities 305
 
  • J.U. Urakawa
    KEK, Ibaraki
 
  The KEK Accelerator Test Facility (ATF) is a 1.3GeV storage ring capable of producing ultra-low emittance electron beams and has a beam extraction line for ILC R&D. The ATF has proven to be an ideal place for researches with small, stable beams. 2x1010 single bunch and low current 20 bunch-train with 2.8nsec bunch spacing have been extracted to develop Nano-Cavity BPM’s, FONT, Nano Beam Orbit handling (FEATHER), Optical Diffraction Radiation (ODR) monitor, a precision multi-bunch laser-based beam profile monitor and polarized positron beam generation via backward-Compton scattering by the international collaboration. A set of three cavity BPM's is installed in the ATF extraction line on a set of extremely stiff supports. The KEK group installed another set of three BPM's, with their own support mechanism. The full set of 6 will prove extremely useful. In the DR (Damping Ring), we are researching the fast ion instability, micro-wave instability with four sets of damping wiggler and developing pulsed laser wire monitor, X-ray SR monitor, very fast kicker with about 1nsec rise/fall time to make ILC beam. I will report the recent results on above R&D’s.  
RPAP011 Technical Development of Profile Measurement for the Soft X-Ray Via Compton Backward Scattering 1260
 
  • T. Saito, Y. Hama, K. Hidume, S. Minamiguchi, A. Oshima, D. Ueyama, M. Washio
    RISE, Tokyo
  • H. Hayano, J.U. Urakawa
    KEK, Ibaraki
  • S. Kashiwagi
    ISIR, Osaka
  • R. Kuroda
    AIST, Tsukuba, Ibaraki
 
  A compact X-ray source is called for such various fields as material development, biological science, and medical treatment. At Waseda University, we have already succeeded to generate the soft X-ray of the wavelength within so-called water window region (250-500eV) via Compton backward scattering between 1047nm Nd:YLF laser and 4.2MeV high quality electron beam. Although this method equips some useful characters, e.g. high intensity, short pulse, energy variableness, etc, the X-ray generating system is compact enough to fit in tabletop size. In the next step, there rises two principal tasks, that is, to make the soft X-ray intensity higher, and to progress X-ray profile measurement techniques as preliminary experiments for biomicroscopy. Specifically, we utilize two-pass amp for the former, and irradiate X-ray to a resist film which is previously exposed by UV lamp or get images with X-ray CCD for the latter. In this conference, we will show the experimental results and some future plans.  
TOAD004 The Possibility of Noninvasive Micron High Energy Electron Beam Size Measurement Using Diffraction Radiation 404
 
  • G.A. Naumenko, A. Potylitsyn
    Tomsk Polytechnic University, Physical-Technical Department, Tomsk
  • S. Araki, A. Aryshev, H. Hayano, V. Karataev, T. Muto, J.U. Urakawa
    KEK, Ibaraki
  • D. Cline, Y. Fukui
    UCLA, Los Angeles, California
  • R. Hamatsu
    TMU, Hatioji-shi,Tokyo
  • M.C. Ross
    SLAC, Menlo Park, California
 
  During the last years a noninvasive method for beam size measurement based on the optical diffraction radiation (ODR) has been in progress (P. Karataev, et al., Physical Review Letters 93, 244802 (2004). However this technique encounters with hard sensitivity limitation for electron energies larger than several GeV. For example, for SLAC conditions the sensitivity of this method is 4 orders smaller than an appropriate one. We suggest to use a "dis-phased" slit target, where two semi-planes are turned with respect to each other at a small "dis-phased" angle. In order to ensure the interference between the diverged radiation beams we use a cylindrical lens. This method has much better sensitivity and resolution. A "dis-phased" angle 10 milliradians gives the optimal sensitivity to 5 microns transversal beam size. The theoretical model for calculating the ODR radiation from such targets (including focusing by cylindrical lens) is presented. It is shown that the sensitivity of this method does not depend on the Lorenz-factor directly. The target with the "dis-phased" angle 6.2 milliradians and the slit width 425 microns was manufactured for experimental test. Some preliminary experimental results are presented.  
WPAP019 X-Band Thermionic Cathode RF Gun at UTNL 1646
 
  • A. Fukasawa, F. Ebina, T. Kaneyasu, H. Ogino, F. Sakamoto, M. Uesaka
    UTNL, Ibaraki
  • M. Akemoto, H. Hayano, T. Higo, J.U. Urakawa
    KEK, Ibaraki
  • K. Dobashi
    NIRS, Chiba-shi
  • K.M. Matsuo, H. Sakae
    IHI/Yokohama, Kanagawa
 
  The X-band (11.424 GHz) linac for compact Compton scattering hard X-ray source are under construction at Nuclear Engineering Research Laboratory, University of Tokyo. This linac designed to accelerate up to 35 MeV, and this electron beam will be used to produce hard X-ray by colliding with laser. It consists of a thermionic cathode RF gun, an alpha magnet, and a traveling wave tube. The gun has 3.5 cells (unloaded Q is 8250) and will be operated at pi-mode. A dispenser cathode is introduced. Since the energy spread of the beam from the gun is predicted to be broad due to the continuous emission from the thermionic cathode, a slit is placed in the alpha magnet to eliminate low energy electrons. The simulation on the injector shows the beam energy 2.9 MeV, the charge 23 pC/bunch, and the emittance less than 10 mm.mrad. The experiment on the gun is planed in the beginning of 2005, and the details will be discussed on the spot.  
RPAP006 X-Band Linac Beam-Line for Medical Compton Scattering X-Ray Source 994
 
  • K. Dobashi
    NIRS, Chiba-shi
  • M. Akemoto, H. Hayano, T. Higo, J.U. Urakawa
    KEK, Ibaraki
  • F. Ebina, A. Fukasawa, T. Kaneyasu, H. Ogino, F. Sakamoto, M. Uesaka, Y. Yamamoto
    UTNL, Ibaraki
 
  Compton scattering hard X-ray source for 10~80 keV are under construction using the X-band (11.424 GHz) electron linear accelerator and YAG laser at Nuclear Engineering Research laboratory, University of Tokyo. This work is a part of the national project on the development of advanced compact medical accelerators in Japan. National Institute for Radiological Science is the host institute and U. Tokyo and KEK are working for the X-ray source. Main advantage is to produce tunable monochromatic hard ( 10-80 keV) X-rays with the intensities of 108-10 photons/s (at several stages) and the table-top size. Second important aspect is to reduce noise radiation at the beam dump by adopting the deceleration of electrons after the Compton scattering. The X-ray yield by the electron beam and Q-switch Nd:YAG laser of 2.5 J/10 ns is 107 photons/RF-pulse (108 photons/sec in 10 pps). X-band beam line for the demonstration is under commissioning. We also design to adopt a technique of laser circulation to increase the X-ray yield up to 109 photons/pulse (1010 photons/s). The construction of the whole system starts. X-ray generation and medical application will be performed in this year.  
RPPP008 The Short Circumference Damping Ring Design for the ILC 1126
 
  • M. Korostelev, F. Zimmermann
    CERN, Geneva
  • K. Kubo, M. Kuriki, S. Kuroda, T. Naito, J.U. Urakawa
    KEK, Ibaraki
  • M.C. Ross
    SLAC, Menlo Park, California
 
  The ILC damping ring tentative design is driven by the operational scenario of the main linac, the beam-dynamics demand of producing a stable and high-quality beam, the injection/extraction scheme and the kicker performance. In this paper, a short circumference damping ring design based on TME cells is described. The ring accommodates injection kickers which provide a flat top of 280 nsec and a 60 nsec rise and fall time and very fast strip-line kickers for beam extraction with a 2 nsec rise and fall time for 3-MHz operation. The potential impact of collective effects and the possible degradation of the dynamic aperture by nonlinear-wiggler fields are estimated.  
FOAB010 Present Status of Photo-Cathode RF Gun System and Its Applications 710
 
  • R. Kuroda, Y. Hama, K. Hidume, M. Kawaguchi, R. Moriyama, T. Saito, K. Sakaue, M. Washio
    RISE, Tokyo
  • H. Hayano, J.U. Urakawa
    KEK, Ibaraki
  • S. Kashiwagi
    ISIR, Osaka
 
  High quality electron beam generation using photo-cathode rf gun system and its applications have been developed at Waseda University. This system can generate up to 4.6 MeV low emittance electron beam. It is applied for soft X-ray generation using laser Compton scattering and pulse radiolysis experiments based on the pump-probe technique. In the former, Compton scattering experiments between about 4.6 MeV electron beam and 1047 nm laser beam is performed at 20 degrees interaction angle, so that about 370 eV soft X-ray is generated. In the latter, the electron beam is used for the pump beam and the probe beam is generated as white light by concentrating laser beam on the water cell, so that the measurement with about 30 ps (FWHM) time resolution of the pulse radiolysis system is demonstrated for the absorption of hydrated electrons. In this conference, we will present the experimental results, status of this system and future applications.  
RPAT077 Beam Test Proposal of an ODR Beam Size Monitor at the SLAC FFTB 4015
 
  • Y. Fukui, D. Cline, F. Zhou
    UCLA, Los Angeles, California
  • A. Aryshev, V. Karataev, T. Muto, M. Tobiyama, J.U. Urakawa
    KEK, Ibaraki
  • P.R. Bolton, M.C. Ross
    SLAC, Menlo Park, California
  • R. Hamatsu
    TMU, Hatioji-shi,Tokyo
  • G.A. Naumenko, A. Potylitsyn, A. Sharafutdinov
    Tomsk Polytechnic University, Physical-Technical Department, Tomsk
 
  We design a single bunch transverse beam size monitor which will be tested to measure the 29 GeV electron/positron beam at the SLAC FFTB beam line.The beam size monitor uses a CCD camera to make images of the interference pattern of the optical diffraction radiation from conductive slit target which are placed close to the beam path. In this method, destruction of the accelerated electron/positron beam bunches due to the beam size monitoring is negligible, which is vital to the operation of the Linear Collider project. A dis-phased conductive slit target and a lens system allow us to recover the sensitivity of the transverse beam size with a small photon yield ratio at the valley to that at the peak due to the large gamma*λ, and with the near field effect due to the large λ*gamma**2. A solution for non-negligible divergence at the SLAC FFTB is also discussed.  
RPPP003 Proposal of the Next Incarnation of Accelerator Test Facility at KEK for the International Linear Collider 874
 
  • H. Hayano, S. Araki, H. Hayano, Y. Higashi, Y. Honda, K.-I. Kanazawa, K. Kubo, T. Kume, M. Kuriki, S. Kuroda, M. Masuzawa, T. Naito, T. Okugi, R. Sugahara, T. Tauchi, N. Terunuma, N. Toge, J.U. Urakawa, V.V. Vogel, H. Yamaoka, K. Yokoya
    KEK, Ibaraki
  • I.V. Agapov, G.A. Blair, G.E. Boorman, J. Carter, C.D. Driouichi, M.T. Price
    Royal Holloway, University of London, Surrey
  • D.A.-K. Angal-Kalinin, R. Appleby, J.K. Jones, A. Kalinin
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • P. Bambade
    LAL, Orsay
  • K.L.F. Bane, A. Brachmann, T.M. Himel, T.W. Markiewicz, J. Nelson, N. Phinney, M.T.F. Pivi, T.O. Raubenheimer, M.C. Ross, R.E. Ruland, A. Seryi, C.M. Spencer, P. Tenenbaum, M. Woodley
    SLAC, Menlo Park, California
  • S.T. Boogert, A. Liapine, S. Malton
    UCL, London
  • H.-H. Braun, D. Schulte, F. Zimmermann
    CERN, Geneva
  • P. Burrows, G.B. Christian, S. Molloy, G.R. White
    Queen Mary University of London, London
  • J.Y. Choi, J.Y. Huang, H.-S. Kang, E.-S. Kim, S.H. Kim, I.S. Ko
    PAL, Pohang, Kyungbuk
  • S. Danagoulian
    North Carolina A&T State University, Greensboro, North Carolina
  • N. Delerue, D.F. Howell, A. Reichold, D. Urner
    OXFORDphysics, Oxford, Oxon
  • J. Gao, W. Liu, G. Pei, J.Q. Wang
    IHEP Beijing, Beijing
  • B.I. Grishanov, P.L. Logachev, F.V. Podgorny, V.I. Telnov
    BINP SB RAS, Novosibirsk
  • J.G. Gronberg
    LLNL, Livermore, California
  • Y. Iwashita, T. Mihara
    Kyoto ICR, Uji, Kyoto
  • M. Kumada
    NIRS, Chiba-shi
  • S. Mtingwa
    North Carolina University, Chapel Hill, North Carolina
  • O. Napoly, J. Payet
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  • T.S. Sanuki, T.S. Suehara
    University of Tokyo, Tokyo
  • T. Takahashi
    Hiroshima University, Higashi-Hiroshima
  • E.T. Torrence
    University of Oregon, Eugene, Oregon
  • N.J. Walker
    DESY, Hamburg
 
  The realization of the International Linear Collider (ILC) will require the ability to create and reliably maintain nanometer size beams. The ATF damping ring is the unique facility where ILC emittancies are possible. In this paper we present and evaluate the proposal to create a final focus facility at the ATF which, using compact final focus optics and an ILC-like bunch train, would be capable of achieving 35nm beam size. Such a facility would enable the development of beam diagnostics and tuning methods, as well as the training of young accelerator physicists.