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Urakawa, J.

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MOPAS024 Fast Extraction Kicker for the Accelerator Test Facility 485
  • S. De Santis
    LBNL, Berkeley, California
  • T. Naito, J. Urakawa
    KEK, Ibaraki
  Funding: Work supported by the U. S. Department of Energy under Contract No. DE-AC0-05CH11231.

We present the final results of a study for the design of a fast extraction kicker to be installed in the Accelerator Test Facility ring at KEK. The purpose of this project is to test the technologies to be used in the design of the extraction kickers for the International Linear Collider damping rings. The kicker's rise and fall times are important parameters in the final configuration of the rings, since they constrain the minimum distance between bunches and ultimately define a lower limit for the rings length. We investigated a stripline kicker composed of several 65-cm long sections, grouped in two different locations in the ATF damping ring. An analytical study of the kicker's parameter and extensive computer simulations using Microwave Studio* point out the ambitious requirements on the pulsers, in order to be able to satisfy the design specifications. We also investigated the use of a single kicker module, together with a close orbit bump near the extraction septum.

* http://www.cst.com

TUPMN049 Improvement of Soft X-ray Generation System Based on Laser Compton Scattering 1031
  • T. Gowa, Y. Kamiya, A. Masuda, R. Moriyama, K. Sakaue, M. Washio
    RISE, Tokyo
  • H. Hayano, J. Urakawa
    KEK, Ibaraki
  • S. Kashiwagi
    ISIR, Osaka
  • R. Kuroda
    AIST, Tsukuba, Ibaraki
  • K. U. Ushida
    RIKEN, Saitama
  Funding: This work is supported by MECSST High Tech Research Center Project No. 707 and JSPS (B) (2) 18340079.

At Waseda University, we have succeeded in generating soft X-rays based on laser Compton scattering. The energies are within "Water Window" part (250~500eV) where the X-ray absorption coefficient of water is much less than that of constituent elements of living body such as carbon, hydrogen and nitrogen. For this reason, it is expected to apply to a bio-microscope with which we can observe living cells without dehydration. To improve the generation system, we remodeled our collision chamber and adopted 3-pass flash lamp amplifier system. With these modifications, we achieved high S/N ratio. The photon number detected by MCP was 278/pulse, tenfold increase of that in last year. Moreover, we succeeded in generating soft X-rays stably for more than 10 hours. Now we are planning to measure two-dimensional distribution of the X-rays by CCD. In this conference, experimental results and future plans will be reported.

TUPMN050 Development of Pulsed-Laser Super-Cavity for Compact X-Ray Source Based on Laser-Compton Scattering 1034
  • K. Sakaue, M. Washio
    RISE, Tokyo
  • S. Araki, M. K. Fukuda, Y. Higashi, Y. Honda, T. Taniguchi, N. Terunuma, J. Urakawa
    KEK, Ibaraki
  • N. Sasao, H. Yokoyama
    Kyoto University, Kyoto
  • M. Takano
    Tsukuba-shi, Ibaraki-ken
  A compact and high quality x-ray source is required from various field, such as medical diagnosis, drug manifacturing and biological sciences. Laser-Compton based x-ray source that consist of a compact electron storage ring and a pulsed-laser super-cavity is one of the solutions of compact x-ray source. Pulsed-laser super-cavity has been developed for a compact high brightness x-ray sources at KEK-ATF. The pulsed-laser super-cavity increases the laser power and stably makes small laser beam size at the collision point with the electron beam. Recently, 357MHz mode-locked Nd:VAN laser pulses can be stacked stably in a 420mm long Fabry-Perot cavity with 1'000 enhancement in our R&D. Therefore, we have planned a compact hard x-ray sources using 50MeV multi-bunch electrons and a pulse stacking technology with 42cm Fabry-Perot cavity. (LUCX Project at KEK) The photon flux is multiplied with the number of bunches by using multi-bunch beam and super-cavity. Development of the super-cavity and present result of LUCX will be presented at the conference.  
WEXAB03 ATF Results and ATF-II Plans 1950
  • J. Urakawa
    KEK, Ibaraki
  The ATF (Accelerator Test Facility at KEK) International collaboration has been launched formally under the MoU (Memorandum of Understanding) from August 1, 2005, so as to maximally contribute to the world design and development efforts in the areas of particle sources, damping rings, beam focusing and beam instrumentation towards the International Linear Collider (ILC) project. I will give a talk on the recent ATF results and future plans of ATF2 project. I am sure that ATF International collaboration group will give a right direction regarding the development of fast kicker for ILC damping ring and clear experimental results on fast ion instability with very flat beam. Several considerations for ATF-II beam commissioning strategy will be discussed with the explanation of the beam instrumentation.  
slides icon Slides  
THPMN028 Development of the Strip-line Kicker System for ILC Damping Ring 2772
  • T. Naito, H. Hayano, K. Kubo, M. Kuriki, N. Terunuma, J. Urakawa
    KEK, Ibaraki
  The performance of the kicker system for the International Linear collider(ILC) is the one of the key component to determine the damping ring(DR) circumference and the train structure. The parameters are discussing at the baseline configuration design for the ILC. The bunch trains in the linac are 2820(5640) bunches with 308(154) ns spacing and the repetition rate is 5Hz. The bunch spacing in the DR is 6(3) ns. The kicker has to have fast rise and fall times of 6(3) ns and the repetition rate of 3.25(6.5) MHz. The development work of the kicker system using multiple strip-lines is carried out at KEK-ATF. The beam test result of the single unit is described. Also Experimental results on new scheme to improve the rise and fall times will be presented.  
THPMN037 Development of Compact EUV Source based on Laser Compton Scattering 2799
  • S. Kashiwagi, R. Kato, J. Yang
    ISIR, Osaka
  • R. Kuroda
    AIST, Tsukuba, Ibaraki
  • K. Sakaue, M. Washio
    RISE, Tokyo
  • J. Urakawa
    KEK, Ibaraki
  High-power extreme ultraviolet (EUV) source is required for next generation semiconductor lithography. We start to develop a compact EUV source in the spectral range of 13-14 nm, which is based on laser Compton scattering between a 7 MeV electron beam and a high intensity CO2 laser pulse. Electron beam is pre-bunched using two different wavelengths of laser pulses with a dispersion section of beam transport line*,**. In this conference, we describe the results of numerical study for the EUV source and a plan of test experiment generating micro-bunched electron beam.

*M. Goldstein et al., Proc. of the 27th Int. FEL conference, Stanford, California, USA (2005) pp.422-425**A. Endo, Sematic EUV source workshop, Barcelona, Spain (2006)

THPMN040 Development of an S-band Cs2Te-Cathode RF Gun with New RF Tuners 2808
  • Y. Kamiya, Y. Kato, A. Murata, K. Sakaue, M. Washio
    RISE, Tokyo
  • N. Kudoh, M. Kuriki, T. T. Takatomi, N. Terunuma, J. Urakawa
    KEK, Ibaraki
  • R. Kuroda
    AIST, Tsukuba, Ibaraki
  We have been studying an S-band Cs2Te-Cathode RF Gun with 1.6 cells. The new gun cavity reported in this poster has new RF tuners, which are compact and, therefore, can be attached even on the half-cell. RF balance between the full- and half-cells is adjustable by using the tuners on both cells. Compared to the existing cavity, a Helicoflex seal for half-cell adjustment is not needed for new one. This structure is expected to have advantages for gun machining, for Q factor of the cavity, and for reduction of dark current from the RF gun. The cathode is made by evaporation on a Mo plug, and the plug is attached by a load lock system. We report status of the gun development.  
THOAC01 ATF Extraction Line Laser-Wire System 2636
  • L. Deacon, G. E. Boorman, L. Deacon
    Royal Holloway, University of London, Surrey
  • A. Aryshev, H. Hayano, K. Kubo, N. Terunuma, J. Urakawa
    KEK, Ibaraki
  • G. A. Blair, S. T. Boogert, A. Bosco, L. Corner, N. Delerue, F. Gannaway, D. F. Howell, V. Karataev, M. Newman, A. Reichold, R. Senanayake, R. Walczak
    JAI, Oxford
  • B. Foster
    OXFORDphysics, Oxford, Oxon
  Funding: PPARC LC-ABD Collaboration Royal Society Daiwa Foundation Commission of European Communities under the 6th Framework Programme Structuring the European Research Area, contract number RIDS-011899

The ATF extraction line laser-wire (LW) aims to achieve a micron-scale laser spot size and to verify that micron-scale beam profile measurements can be performed at the International Linear Collider beam delivery system. Recent upgrades to the LW system are presented together with recent results including the first use of the LW as a beam diagnostic tool.

slides icon Slides  
THPMN032 Beam Generation and Acceleration Experiments of X-Band Linac and Monochromatic keV X-Ray Source of the University of Tokyo 2784
  • F. Sakamoto, T. Natsui, Y. Taniguchi, M. Uesaka, T. Yamamoto
    UTNL, Ibaraki
  • M. Akemoto, T. Higo, J. Urakawa
    KEK, Ibaraki
  • D. Ishida, N. Kaneko, H. Nose, H. Sakae, Y. Sakai
    IHI/Yokohama, Kanagawa
  • M. Yamamoto
    Akita National College of Technology, Akita
  In the Nuclear Professional School, the University of Tokyo, we are constructing an X-band linear accelerator that consists of an X-band thermionic cathode RF gun and X-band accelerating structure. This system is considered for a compact inverse Compton scattering monochromatic X-ray source for the medical application. The injector of this system consists of the 3.5-cell coaxial RF feed coupler type X-band thermionic cathode RF gun and an alpha-magnet. The X-band accelerating structure is round detuned structure (RDS) type that developed for the future linear collider are fully adopted. So far, we have constructed the whole RF system and beam line for the X-band linac and achieved 2 MeV electron beam generation from the X-band thermionic cathode RF gun. In addition, we achieved 40 MW RF feeding to the accelerating structure. The laser system for the X-ray generation via Compton scattering was also constructed and evaluated its properties. In this presentation, we will present the details of our system and progress of beam acceleration experiment and the performance of the laser system for the Compton scattering experiment.  
THPAN038 Generation and Acceleration of High Brightness Electron Bunch Train in ATF of KEK 3312
  • S. Liu, S. Araki, M. K. Fukuda, M. Takano, N. Terunuma, J. Urakawa
    KEK, Ibaraki
  • K. Hirano
    NIRS, Chiba-shi
  Laser Undulator Compact X-ray source (LUCX) is a test bench for compact high brightness X-ray generator at KEK in order to demonstrate the possibility on K-edge digital subtraction angiography, based on the Compton Scattering. For this project, one of the challenging problems is to generate and accelerate high brightness multi-bunch electron beams, compensating the energy difference due to beam loading effect. In this paper, we calculate the transient beam loading voltage and energy gain from RF field in standing wave gun cavity and traveling wave accelerating tube for multi-bunch train, considering the process of propagation, buildup of RF field in them and the special RF pulse shape. We generated and accelerated 100 bunch electron beam train with 50nC, which beam loading effect was compensated effectively by adjusting the laser injection timing. By BPM and OTR system, we measured the electron beam energy bunch by bunch. The average energy of 100 bunch train is 40.5MeV and maximum energy difference bunch to bunch is 0.26MeV, the relative energy spread of single bunch is about 0.13%. The transverse emittance can be optimized roughly to 3.6 pimm.mrad.  
FRPMN054 The Design Study of IP-BPM for the ILC 4120
  • S. H. Shin, E.-S. Kim, H.-S. Kim
    Kyungpook National University, Daegu
  • Y. Honda, J. Urakawa
    KEK, Ibaraki
  Beam position monitors (BPMs) with a resolution in a few nanometers range are required to control beams in the locations that are close to the interaction point (IP) of the International Linear Collider (ILC). ATF2 at KEK has considered as a test facilitiy to investigate this requirement. We have performed the design study for IP-BPM by using of the electromagnetic simulation program MAFIA and HFSS. The designed IP-BPM consists of one cell sensor cavity and one cell reference cavity. The results of the design studies showed signal decay time of 20 ns and orbit sensitivity of a few nm. The signal voltage from sensor cavity showed increasing of a factor of 3 and 2 in horizontal and vertical directions, respectively, than the IP-BPM that was installed ATF extraction beam line. We present the results of design studies in which include effects of common mode contamination in the IP-BPM.  
FRPMS049 Resolution of a High Performance Cavity Beam Position Monitor System 4090
  • S. Walston, C. C. Chung, P. Fitsos, J. Gronberg
    LLNL, Livermore, California
  • S. T. Boogert
    Royal Holloway, University of London, Surrey
  • J. C. Frisch, S. Hinton, J. May, D. J. McCormick, S. Smith, T. J. Smith, G. R. White
    SLAC, Menlo Park, California
  • H. Hayano, Y. Honda, N. Terunuma, J. Urakawa
    KEK, Ibaraki
  • Yu. G. Kolomensky, T. Orimoto
    UCB, Berkeley, California
  • P. Loscutoff
    LBNL, Berkeley, California
  • A. Lyapin, S. Malton, D. J. Miller
    UCL, London
  • R. Meller
    Cornell University, Department of Physics, Ithaca, New York
  • M. C. Ross
    Fermilab, Batavia, Illinois
  • M. Slater, M. Thomson, D. R. Ward
    University of Cambridge, Cambridge
  • V. Vogel
    DESY, Hamburg
  International Linear Collider (ILC) interaction region beam sizes and component position stability requirements will be as small as a few nanometers. It is important to the ILC design effort to demonstrate that these tolerances can be achieved – ideally using beam-based stability measurements. It has been estimated that RF cavity beam position monitors (BPMs) could provide position measurement resolutions of less than one nanometer and could form the basis of the desired beam-based stability measurement. We have developed a high resolution RF cavity BPM system. A triplet of these BPMs has been installed in the extraction line of the KEK Accelerator Test Facility (ATF) for testing with its ultra-low emittance beam. A metrology system for the three BPMs was recently installed. This system employed optical encoders to measure each BPM's position and orientation relative to a zero-coefficient of thermal expansion carbon fiber frame and has demonstrated that the three BPMs behave as a rigid-body to less than 5 nm. To date, we have demonstrated a BPM resolution of less than 20 nm over a dynamic range of ± 20 microns.