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Suwada, T.

Paper Title Page
TUP009 Development of Timing and Control Systems for Fast Beam Switch at KEK 8 GeV Linac 404
 
  • K. Furukawa, M. Satoh, T. Suwada
    KEK, Ibaraki
  • A. Kazakov
    GUAS/AS, Ibaraki
  • T. Kudou, S. Kusano
    MELCO SC, Tsukuba
  • G. Lei, G.X. Xu
    IHEP Beijing, Beijing
 
 

The 8 GeV Linac at KEK provides electrons and positrons to Photon Factory (PF) and B-Factory (KEKB). Simultaneous top-up injections have been considered for both PF and KEKB rings in order to improve the injection efficiency and the stability. Fast beam-switching mechanisms are being implemented, upgrading the timing and control systems. While the present system provides precise timing signals for 150 devices, many of the signals will be dynamically switched using an event system. A new scheme has been developed and tested to enable double-fold synchronization between rf signals. Fast controls of low-level rf, beam instrumentation, a kicker, a gun, and beam operation parameters will also be upgraded.

 
TUP010 Pulse-to-Pulse Mode Switching of KEKB Injector Linac 407
 
  • T. Kamitani, K. Furukawa, N. Iida, M. Ikeda, K. Kakihara, M. Kikuchi, T. Mimashi, S. Ohsawa, M. Satoh, A. Shirakawa, T. Sugimura, T. Suwada, K. Yokoyama
    KEK, Ibaraki
 
 

KEKB injector linac supplies electron and positron beams to the KEKB storage rings and the synchrotron radiation facility rings (PF, AR) as well. Injection modes to these four destinations are switched by inserting and extracting positron generation target, changing magnet parameters and acceleration rf phases. To enable pulse-by-pulse switching in three out of the four modes, a pulse bend and pulse steerings are introduced. For DC quads and DC steerings, compatible beam-optical settings for beams of different beam-energy profiles are introduced. We have been performing beam studies to establish the pulse-by-pulse mode switching for daily beam operation. This paper describes a scheme for the mode switching and reports on an achievement of the beam studies.

 
TUP079 Operational Performance of a New Beam-Charge Interlock System for Radiation Safety at the KEKB Injector Linac 579
 
  • T. Suwada, K. Furukawa, E. Kadokura, M. Satoh
    KEK, Ibaraki
 
 

A new beam-charge interlock system has been developed for radiation safety and machine protection at the KEKB injector linac. Although the previous software-based interlock system was working, it was replaced by the new hardware-based one. The new interlock system restricts the integrated amount of beam charges delivered to four different storage rings (KEKB e+, KEKB e-, PF, PF-AR) at six locations along the linac. When the integrated amount of beam charges exceeds a certain threshold level prescribed at each location, the beam-abort requests are directly sent through a twisted hardwire cable to the safety control system of the linac. The new interlock system boosted its reliability in comparison with the previous system. The full-scale operation of the new interlock system has been started since the end of March 2008. In this report we describe the operational performance of the new beam-charge interlock system.

 
TUP080 Numerical Study of a New Bunch Length Monitor Utilizing a Detection of Electromagnetic Fields in Millimeter-Wave Region 582
 
  • T. Suwada, M. Satoh
    KEK, Ibaraki
 
 

A new nondestructive bunch-length monitor has been numerically investigated. The monitor detects electromagnetic fields generated through a ceramic gap of a vacuum pipe when a charged particle beam passes through the pipe gap. The frequency spectrum of the electromagnetic fields detected in wave zone spreads over a millimeter-wave length from a microwave length region for a short pulse beam with a bunch length of pico-second region. The frequency spectrum strongly depends on the bunch length of the relativistic charged beam if the geometrical structure of the pipe gap is fixed. The detection principle of the bunch-length monitor and some numerical analysis results applied to a single-bunch electron beam of the KEKB injector linac are described in this report.