Paper | Title | Page |
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MOZAKI01 | Compensation of the Crossing Angle with Crab Cavities at KEKB | 27 |
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The crab cavities are presently being installed in the KEKB rings to compensate the crossing angle at collision and thus increase luminosity. This will be the first experience with such cavities in colliders. Results on the beam operation of the new cavities, both for single and colliding beams, will be presented including the luminosity performance and limitations.
Work presented on behalf of the KEKB Accelerator Group. |
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Slides | |
WEPMN028 | Development of Digital Low-level RF Control System using Multi-intermediate Frequencies | 2110 |
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Digital low level rf (LLRF) control system has been developed in Superconducting RF Test Facility (STF) at KEK to carry out the accelerating electric field stability of 0.3% (rms) in amplitude and 0.3 degree (rms) in phase, respectively. In the digital LLRF system, rf probe signal from cavity is down-converted to intermediate frequency (IF) for acquisition at analog-to-digital converter (ADC) and the number of ADCs required is equal to the number of cavities. In order to decrease the number of ADCs, a new digital LLRF control system is under development. In this LLRF system, rf signals are down-converted to different IF and combined. The combined signal is detected with one ADC and I/Q components of each rf signal are calculated with digital signal processing. This paper describes a result of simulation and estimation using cavity simulator based on FPGA board about this new technique. | ||
WEPMN029 | Status of the Low-Level RF System at KEK-STF | 2113 |
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RF field stabilities of less than 0.3%, 0.3deg. are required at STF llrf system. In order to satisfy these requirements, digital FB system using a FPGA is adopted. The FB system consists of a FPGA (VirtexIIPro30) with ten 16-bit ADCs and two 14-bit DACs. The rf (1.3 GHz) probe signals are downconverted to the IF (10 MHz) and directly acquired at ADCs. Total 8 cavities will be installed at STF-Phase 1 in 2007 and vector sum control of 8 cavity signals will be carried out. The performance of the FB system is examined with electric cavity simulators prior to the rf operation. | ||
TUPAN045 | Beam Operation with Crab Cavities at KEKB | 1487 |
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Beam operation with crab cavities is planned in early 2007 at KEKB. The crab crossing scheme is expected to increase the vertical beam-beam tune-shift parameter significantly. One crab cavity will be installed in each ring where conditions for beam optics are matched to compensate the beam crossing angle of 22 mrad. Operation results on collision tuning with the crab cavities will be presented.
For the KEKB Accelerator Group. |