| Paper | Title | Page |
|---|---|---|
| TUP009 | Development of Timing and Control Systems for Fast Beam Switch at KEK 8 GeV Linac | 404 |
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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. |
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| TUP010 | Pulse-to-Pulse Mode Switching of KEKB Injector Linac | 407 |
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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. |
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| TUP012 | Design and Performance of Optics for Multi-energy Injector Linac | 413 |
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KEK injector linac provides an injection beam for four storage rings, KEKB high energy electron ring(HER), low energy positron ring(LER), PF-AR electron ring, and PF electron ring. The injection beams for these rings have different energies and intensities. Recently, a requirement of simultaneous injection among these rings arises to make a top-up injection possible. Magnetic fields of DC magnets to confine the beam to the accelerating structures can not be changed between pulse to pulse, although the beam energy can be controlled by fast rf phase shifters of klystrons. This implies that a common magnetic field of the bending magnets and the quadrupole magnets should be utilized to deliver beams having different characteristics. Therefore, we have designed multi-energy optics for the KEKB-HER electron ring(8 GeV, 1 nC/pulse), the PF electron ring(2.5 GeV, 0.1 nC/pulse), and the KEKB-LER positron ring(3.5 GeV, 0.4 nC/pulse). We present a performance of the multi-energy injector linac. |
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| TUP079 | Operational Performance of a New Beam-Charge Interlock System for Radiation Safety at the KEKB Injector Linac | 579 |
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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. |