Author: Fukuda, S.
Paper Title Page
TUPPD032 Design Optimization of Flux Concentrator for SuperKEKB 1473
  • L. Zang, S. Fukuda, T. Kamitani, Y. Ogawa
    KEK, Ibaraki, Japan
  For high luminosity electron-positron colliders, intense positron beam production is one of the key issues as well as electron. Flux Concentrator (FC) is a pulsed solenoid that can generate high magnetic field of several Tesla and is often used for focusing positrons emerged from a production target. It works as an optical matching device in a positron capture section. With this device, high capture efficiency is achieved. In this paper, we will discuss a design optimization of a FC for the SuperKEKB positron source. Geometrical parameters of the FC are optimized to achieve high peak field using the CST EM Studio. Magnetic field distribution evaluated with the EM Studio is implemented into a particle tracking code to see a performance of the positron capture section. The tracking simulation includes a positron production at the target, focusing by the FC and subsequent solenoids and acceleration by RF structures till the end of the capture section. We report the results of a FC design optimized for higher positron yield with the tracking simulation.  
TUPPR005 Linac Upgrade in Intensity and Emittance for SuperKEKB 1819
  • T. Higo, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, K. Furukawa, Y. Higashi, H. Honma, 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, M. Satoh, T. Shidara, A. Shirakawa, H. Sugimoto, T. Suwada, T. Takatomi, T. Takenaka, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou
    KEK, Ibaraki, Japan
  • D. Satoh
    TIT, Tokyo, Japan
  The SuperKEKB is designed to produce 40 times luminosity than that of the KEKB. In order to realize such a high luminosity, the injector linac should provide both electron and positron beams of about 4-5 nC/bunch, which is several times higher than before. In addition, their emittance requirement of the injection beam to the rings is 20 microns, which is a factor of a few tens smaller than before. The intensity and emittance of the electron beam are realized directly by developing the photo RF gun. In contrast, the positron intensity is increased by adopting a higher capture efficiency system with flux concentrator followed by large-aperture accelerators, while its emittance is reduced by a damping ring. For preserving such a low emittance of both beams toward the injection to the rings, the suppression of the emittance growth is crucial. To this end, the alignment of the accelerator components should be a few tens of microns, where we need an improvement by more than a factor 10. The beam-based alignment is definitely needed with better-resolution BPMs. In the present paper are reviewed the overall progress and perspective of the design and the associated component developments.  
THPPC055 Permanent Magnet Focusing System for Klystrons 3413
  • Y. Fuwa, Y. Iwashita, H. Tongu, S. Ushijima
    Kyoto ICR, Uji, Kyoto, Japan
  • S. Fukuda
    KEK, Ibaraki, Japan
  The Distributed RF System (DRFS) for ILC requires thousands of klystrons. The failure rate of the power supply for solenoid focusing coil of each klystron may be harmful to a regular operation of the ILC. In order to eliminate the power supplies and the cooling system for the coils, a permanent magnet beam focusing system is under development. It will help to reduce the power consumption as well. In our design, a unidirectional magnetic field configuration is adopted to eliminate the stop bands that arise from the periodic permanent magnet configuration. Since the required magnetic field is not high in this case, inexpensive anisotropic ferrite magnets can be used instead of magnets containing rare earth materials. On the basis of a half scaled model fabricated to evaluate the mechanical design, a full scaled model will be ready soon. In order to prove its feasibility, a power test of the klystron for DRFS with this magnet system is planned. The result of magnetic field distribution measurement and the power test will be presented.