Author: Natsui, T.
Paper Title Page
TUOCB103 Quasi Traveling Wave Side Couple RF Gun for SuperKEKB 1117
  • T. Natsui, Y. Ogawa, M. Yoshida, X. Zhou
    KEK, Ibaraki, Japan
  We are developing a new RF gun for SuperKEKB. High charge low emittance electron and positron beams are required for SuperKEKB. We will generate 7.0 GeV electron beam at 5 nC 20 mm-mrad by J-linac. In this linac, a photo cathode S-band RF gun will be used as the electron beam source. For this reason, we are developing an advanced RF gun. We have tested a Disk and Washer (DAW) type RF gun. Additionally, another new RF gun which has two side coupled standing wave field is developed. We call it quasi traveling wave side couple RF gun. This gun has a strong focusing field at the cathode and the acceleration field distribution also has a focusing effect. The design of RF gun and experimental results will be shown.  
slides icon Slides TUOCB103 [2.959 MB]  
TUPEA065 Design of a Photonic Crystal Accelerator for Basic Radiation Biology 1283
  • A. Aimidula, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • A. Aimidula, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • K. Koyama, Y. Matsumura
    University of Tokyo, Tokyo, Japan
  • T. Natsui, M.Y. Yoshida
    KEK, Ibaraki, Japan
  • M. Uesaka
    The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
  • G.X. Xia
    UMAN, Manchester, United Kingdom
  Funding: This work is supported by the EU under Grant Agreement 289485, the STFC Cockcroft Institute Core Grant No. ST/G008248/1 and KAKENHI, Grant-in-Aid for Scientific Research (C) 24510120.
The application of photonic crystals to realize an on-chip electron beam source for fundamental radiation biology is highly interesting for a number of applications. The unique combination of nanometer beam size and attosecond-short pulses has a very promising potential for use in microscopic and ultra-fast analyses of damage and repair of radiation-irradiated DNA and chromosomes. Simulations studies indicate an output electron beam energy, beam intensity and device size of the order of MeVs, fCs and a few cm, respectively. In this contribution, first results from numerical studies into the design of such compact accelerator structure are presented. The dimensions of a novel dual grating-based acceleration structure are shown together with the estimated laser parameters. Finally, a system consisting of an electron injector and multi-stage accelerating structures is proposed, which corresponds to a miniaturized optical linear accelerator.
TUPFI004 Longitudinal Manipulation to Obtain and Keep the Low Emittance and High Charge Electron Beam for SuperKEKB Injector 1337
  • M. Yoshida, N. Iida, T. Natsui, Y. Ogawa, S. Ohsawa, H. Sugimoto, L. Zang, X. Zhou
    KEK, Ibaraki, Japan
  The design strategy of SuperKEKB is based on the.nano-beam scheme. The dynamic aperture decreases due to the very small beta function at the interaction point. Thus the injector upgrade is required to obtain the low emittance and high charge beam corresponding to the short beam life and small injection acceptance. The required beam parameters are 5 nC, 20 mm mrad and 4 nC, 6 mm mrad for the electron and positron respectively. For the electron beam, we installed new photocathode RF-Gun with the focusing electric field and temporal adjusting laser system. Further the projected emittance dilution in the LINAC is an important issue for the low emittance injection. The longitudinal bunch length and shape is an important key to avoid the space charge effect and emittance dilution. The longitudinal manipulation using the temporal adjusting laser system and the bunch compression will be presented. Further the longitudinal bunch measurement will be also presented.  
TUPME010 High-intensity and Low-emittance Upgrade of 7-GeV Injector Linac towards SuperKEKB 1583
  • K. Furukawa, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, H. Honma, R. Ichimiya, N. Iida, M. Ikeda, E. Kadokura, K. Kakihara, T. Kamitani, H. Katagiri, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Miura, F. Miyahara, T. Mori, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, S. Ohsawa, F. Qiu, M. Satoh, T. Shidara, A. Shirakawa, H. Sugimoto, T. Suwada, T. Takatomi, T. Takenaka, M. Tanaka, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou
    KEK, Ibaraki, Japan
  • D. Satoh
    TIT, Tokyo, Japan
  After a decade of successful operation at KEKB a new electron/positron collider, SuperKEKB, is being constructed to commission within FY2014. It aims at a luminosity of 8 x 1035 /s.cm2, 40-times higher than that of KEKB, in order to study the flavor physics of elementary particles further, by mainly squeezing the beams at the collision point. The injector linac should provide high-intensity and low-emittance beams of 7-GeV electron and 4-GeV positron by newly installing a RF-gun, a flux concentrator, and a damping ring with careful emittance and energy management. It also have to perform simultaneous top-up injections into four storage rings by pulse-to-pulse beam modulations not to interfare between three facilities of SuperKEKB, Photon Factory and PF-AR. This paper describes the injector design decisions and present status of the construction.  
WEPME018 Ytterbium Laser Development of DAW RF Gun for SuperKEKB 2965
  • X. Zhou, T. Natsui, Y. Ogawa, M. Yoshida
    KEK, Ibaraki, Japan
  For obtaining higher luminosity in the SuperKEKB, the photocathode RF electron gun with strong electric focusing field for high-current, low-emittance beams will be employed in the injector linac. The electron beams with a charge of 5 nC and a normalized emittance of 10 μm are expected to be generated in the photocathode RF gun by using the laser source with a center wavelength of 260 nm and a pulse width of 30 ps. Furthermore, for reducing the emittance, the laser pulse width should be reshaped from Gaussian to rectangle structure. Therefore, Ytterbium (Yb)-doped laser system that provides broader bandwidth, higher amplify efficiency and higher output power is employed. The laser system starts with a large mode-area Yb-doped fiber-based amplifier system, which consists of a passively mode-locked femtosecond Yb-fiber oscillator and two steps Yb-fiber amplifier. To obtain the several 10mJ-class pulse energy, a Yb:YAG thin-disk regenerative solid-state amplifier is employed. Deep UV pulses for the photocathode are generated by using two frequency-doubling stages. High pulse energy and good stability would be expected.