| Paper |
Title |
Page |
| WEPB02 |
Design of an Intra-Bunch-Train Feedback System for the European X-Ray FEL
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232 |
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- B. Keil, G. J. Behrmann, M. Dehler, R. Kramert, G. Marinkovic, P. Pollet, M. Roggli, M. Rohrer, T. Schilcher, V. Schlott, D. M. Treyer
PSI, Villigen
- J. Lund-Nielsen, D. Nölle, M. Siemens, S. Vilcins
DESY, Hamburg
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After joining the preparatory phase of the European X-ray FEL project, the Paul Scherrer Institute agreed in taking over responsibility for electron beam stabilization by developing a fast intra-bunch-train feedback (IBFB) system, which will be tested in its prototype version at the FLASH linac of the collaboration partner DESY. The proposed IBFB topology consists of two beam position monitors ("upstream BPMs") followed by two kicker magnets for each transverse plane and two more BPMs ("downstream BPMs"). By measuring the position of each bunch at the upstream BPMs and applying suitable transverse kicks individually to the following bunches, the architecture of the FPGA-based digital IBFB electronics (with a latency preferably below the bunch spacing of 200 ns and 1000 ns for the XFEL and FLASH) allows to damp beam motions up to hundreds of kHz. In addition to the FPGA-based feedback, DSPs enable adaptive feed-forward correction of repetitive beam motions as well as feedback parameter optimisation using the downstream BPMs. This paper gives an overview of the architecture and status of the IBFB subsystems being developed, like stripline BPMs, digital electronics and kicker magnets.
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| WEO3A01 |
Low-Latency High-Resolution Single-Shot Beam Position Monitors
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376 |
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- D. M. Treyer
PSI, Villigen
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In this paper design aspects of high-resolution, single-shot transverse beam position monitors (BPMs) are discussed. The focus is put on BPMs which can provide (sub-)micrometer precision at measurement speeds of less than a few hundred nanoseconds. Different pickups, analog signal conditioning electronics, and digital post processing schemes are reviewed. Their characteristics and limitations with respect to application in high-resolution, fast BPMs are pointed out. Exemplary implementations of successful BPM realizations found in the literature are reviewed. A specific implementation of a BPM based on a resonant stripline pickup, developed for a fast transverse feedback system for the European X-FEL, is also presented.
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