| Paper | Title | Page |
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| TH5RFP004 | First Full-Sector Closed-Loop Operational Experience for the FPGA-Based Broadband Beam Position Monitor at the APS | 3441 |
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Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06CH11357. The Advanced Photon Source (APS), a third-generation synchrotron light source, has been in operation for eleven years. The monopulse radio frequency (rf) beam position monitor (BPM) is one of three BPM types now employed in the storage ring at the APS. It is a broadband (10 MHz) system designed to measure single-turn and multi-turn beam positions, but it suffers from an aging data acquisition system. The replacement BPM system retains the existing monopulse receivers and replaces the data acquisition system with high-speed analog-to-digital converters (ADCs) and a field-programmable gate array (FPGA) that performs the signal processing. The new system has been installed and commissioned in a full sector of the APS. This paper presents the results of testing of the beam position monitor which is now fully integrated into the storage ring orbit control and fast feedback systems. |
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| TH6REP086 | A Stable Phase Reference for the APS Short-Pulse X-Ray Project | 4159 |
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Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357 The Argonne Advanced Photon Source is in the process of developing a short-pulse x-ray (SPX) beamline capable of producing picosecond-scale x-ray pulses for use in time-resolved studies. To accomplish this, transverse deflecting cavities (crab cavities) operating at eight times the storage ring rf will be installed to enable production of short x-ray pulses at a selected beamline. Analysis reveals demanding phase and amplitude stability requirements for the cavity fields. The common-mode cavity field phase error relative to bunch arrival time is ± 10 degrees at the 2815-MHz cavity frequency while the cavity-to-cavity phase difference must be held to ± 0.07 degrees. The phase differential between the cavity phase and beamline timing must be held to ± 1 picosecond. A phase stabilized link* is being developed to transport a phase stable 351.9-MHz reference to the LLRF located at the beamline end. The delivered phase-stable reference will be used to develop rf references for the cavity LLRF, beamline laser, and streak camera. This paper will discuss the details of the design and report measured performance of the prototype. * J. Frisch, D. Bernstein, D. Brown, E. Cisnerso, “A High Stability, Low Noise RF Distribution System,“ Proceedings of PAC2001, pp 816-818. |