Paper |
Title |
Page |
WEOBM02 |
Lessons Learned from PEP-II LLRF and Longitudinal Feedback
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1953 |
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- J. D. Fox, T. Mastorides, C. H. Rivetta, D. Van Winkle
SLAC, Menlo Park, California
- D. Teytelman
Dimtel, San Jose
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The PEP-II B Factory is in the final phase of operation at 2X the design current and 4X the design luminosity. Since the original design the machine has added 8 1.2 MW Klystrons and 12 RF cavities, and the machine is operating with longitudinal instability growth rates roughly 5X in excess of the original estimates. Since commissioning there has been continual adaptation of the LLRF control strategies, configuration tools and new hardware in response to unanticipated technical challenges. This paper presents the LLRF and feedback system evolution from the original design estimates through to the 1.2·1034 final machine. We highlight issues of RF station stability, the interplay of LLRF configuration and low-mode (cavity fundamental driven) longitudinal instabilities, impacts of non-linearities and imperfections in the LLRF electronics, control of HOM driven beam instabilities and the development of configuration tools and measurement techniques to optimally configure the LLRF over the wide range of operating currents. We present valuable "lessons learned" which are of interest to designers of next generation impedance controlled LLRF systems.
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Slides
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WEXG02 |
Crabbed Waist Collisions in DAΦNE and Super-B Design
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1898 |
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- P. Raimondi, D. Alesini, M. E. Biagini, C. Biscari, R. Boni, M. Boscolo, F. Bossi, B. Buonomo, A. Clozza, G. O. Delle Monache, T. Demma, E. Di Pasquale, G. Di Pirro, A. Drago, A. Gallo, A. Ghigo, S. Guiducci, C. Ligi, F. Marcellini, G. Mazzitelli, C. Milardi, F. Murtas, L. Pellegrino, M. A. Preger, L. Quintieri, R. Ricci, U. Rotundo, C. Sanelli, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, S. Tomassini, C. Vaccarezza, M. Zobov
INFN/LNF, Frascati (Roma)
- N. Arnaud, D. Breton, P. Roudeau, A. Stocchi, V. Variola, B. F. Viaud
LAL, Orsay
- S. Bettoni
CERN, Geneva
- P. Branchini
roma3, Rome
- M. Esposito
Rome University La Sapienza, Roma
- I. Koop, E. B. Levichev, P. A. Piminov, D. N. Shatilov, V. V. Smaluk
BINP SB RAS, Novosibirsk
- K. Ohmi
KEK, Ibaraki
- E. Paoloni
University of Pisa and INFN, Pisa
- M. Schioppa
INFN Gruppo di Cosenza, Arcavacata di Rende (Cosenza)
- D. Teytelman
SLAC, Menlo Park, California
- P. Valente
INFN-Roma, Roma
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The new idea of increasing the luminosity of a collider with crabbed waist collisions and first experimental results from DAΦNE using this concept are presented. Consequences for the design of future factories will be discussed. An outlook to the performance reach with crabbed waist collisions is given, with emphasis on future B Factories.
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Slides
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THPC116 |
Commissioning of the iGp Feedback System at DAΦNE
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3251 |
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- A. Drago
INFN/LNF, Frascati (Roma)
- J. D. Fox
SLAC, Menlo Park, California
- D. Teytelman
Dimtel, San Jose
- M. Tobiyama
KEK, Ibaraki
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The iGp (Integrated Gigasample Processor) is an innovative digital bunch-by-bunch feedback system developed by a KEK/SLAC/INFN-LNF joint collaboration. The processing unit can sample at 500 MHz and compute the bunch-by-bunch output signal for up to 5000 bunches. The feedback firmware code is implemented inside just one FPGA (Field Programmable Gate Array) chip, a Xilinx Virtex-II. The FPGA implements two 16 taps FIR (Finite Impulse Response) filter that are realtime programmable through the operator interface. At DAΦNE, the Frascati PHI-Factory, two iGp units have been commissioned in the April 2007. The iGp systems have plugged in the previous betatron feedback systems. This insertion has been very fast and has shown no problems involving just a substitution of the old, less flexible, digital unit, letting unchanged the baseband analog frontend and the analog backend. The commissioning has been very simple, due to the complete and powerful EPICS operator interface, working well in local and remote operations. The software includes also tools for analyzing post processor data. A description of the commissioning with the operations done to find the best feedback setup are reported.
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THPP003 |
RF System Design for the EMMA FFAG
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3377 |
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- C. D. Beard, S. A. Griffiths, C. Hill, P. A. McIntosh, A. E. Wheelhouse
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
- N. Bliss, A. J. Moss, C. J. White
STFC/DL, Daresbury, Warrington, Cheshire
- D. Teytelman
Dimtel, San Jose
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In this report the RF system design for EMMA is described. The power source options, power supplies, waveguide distribution scheme and control system is discussed. The architecture necessary to meet the operation specifications requires a large degree of adjustment. To simplify commissioning and enhance the versatility of the machine a complex RF system is desired. This report details the RF "knobs" included to meet this.
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