| Title |
Low Q Cavity BPM Study for the Beam Position Measurement of Nanosecond Spaced Electron Bunches |
| Authors |
- L. Yang, X. Hepresenter, L.W. Zhang
CAEP/IFP, Mainyang, Sichuan, People's Republic of China
- S.S. Cao, Y.B. Leng, L.Y. Yu, R.X. Yuan
SINAP, Shanghai, People's Republic of China
|
| Abstract |
Low Q cavity BPM is a key to distinguish closely spaced electron bunches allowing precise beam handling for XFEL facilities operating in a multi-bunch mode at high repetition rate up to hundreds MHz. The inter-bunch signal pollution issue becomes significant when bunch separation is down to nanosecond and causes the position detection to be increasingly overestimated. Solely relying on extreme low Q to achieve sufficient decay within bunch interval leads to appreciable interference from non-signal modes due to strong overcoupling of antenna design is required. The error imposed on measured position raises a challenge to meet the goal of high resolution. Alternatively, a concept is proposed to remove the dominant part of signal pollution at the moment of sampling by intentionally shifting the phase of the last bunch signal 90degree respect to that of current bunch signal, where signal sampling is normally taken for nanosecond spaced bunches. This quadrature phase shift is defined by properly choosing the operational frequency of dipole mode regarding to the bunch frequency. A low Q cavity BPM prototype to identify technical challenges and verify this concept is under development in the R&D plan for future XFEL with high repetition rate
|
| Funding |
National natural science foundation of China, 11705184 |
| Paper |
download WEPAF027.PDF [0.948 MB / 3 pages] |
| Export |
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| Conference |
IPAC2018, Vancouver, BC, Canada |
| Series |
International Particle Accelerator Conference (9th) |
| Proceedings |
Link to full IPAC2018 Proccedings |
| Session |
MC6 Poster Session |
| Date |
02-May-18 09:00–12:00 |
| Main Classification |
06 Beam Instrumentation, Controls, Feedback, and Operational Aspects |
| Sub Classification |
T03 Beam Diagnostics and Instrumentation |
| Keywords |
cavity, FEL, dipole, electron, coupling |
| Publisher |
JACoW Publishing, Geneva, Switzerland |
| Editors |
Shane Koscielniak (TRIUMF, Vancouver, BC, Canada); Todd Satogata (JLab, Newport News, VA, USA); Volker RW Schaa (GSI, Darmstadt, Germany); Jana Thomson (TRIUMF, Vancouver, BC, Canada) |
| ISBN |
978-3-95450-184-7 |
| Published |
June 2018 |
| Copyright |
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