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ILCDR/CesrTA meeting Low Emittance Tuning 報告

ILCDR/CesrTA meeting Low Emittance Tuning 報告. 200807 K.Kubo. ILCDR08 workshop + CesrTA meeting. 2008. 7.8 ~ 11 at Cornell Two topics: Electron Cloud (main issue)  末次報告 Low emittance tuning  久保報告 参加者　 ~40 (E-cloud : LET ~ 2:1) 日本 (KEK) から７人. Mark Palmer & David Rubin.

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ILCDR/CesrTA meeting Low Emittance Tuning 報告

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  1. ILCDR/CesrTA meeting Low Emittance Tuning 報告 200807 K.Kubo

  2. ILCDR08 workshop + CesrTA meeting • 2008. 7.8 ~ 11 at Cornell • Two topics: • Electron Cloud (main issue) 末次報告 • Low emittance tuning  久保報告 • 参加者　~40 (E-cloud : LET ~ 2:1) • 日本(KEK)から７人

  3. Mark Palmer & David Rubin

  4. Mark Palmer & David Rubin

  5. Mark Palmer & David Rubin

  6. Low Emittance Tuning session • Overview, A.Wolski • Experimental Plan for low emittance in CesrTA, David Rubin • Talks on Instrumentation and measurement techniques • Reports of machine experiences and tuning methodes • Modeling and plans for future machines • Modeling and plans for CesrTA • Discussions, plans for CesrTA, Collaborations

  7. Overview by A.Wolski • Design issues of ILC DR • Low emittance, <=2 pm • Difficulties depend on design (no clear conclusion) • The three-pronged approach: • Modeling and simulations • Instrumentation and diagnostics • Experience of existing machine

  8. Experimental Plan for low emittance in CesrTA, David Rubin • CesrTA lattice • Sensitivity of vertical emittance to optical and alignment errors • Beam based alignment • Beam position monitor upgrade • Survey • Dispersion measurement and correction • Coupling measurement and correction • Beam size monitor • Lifetime as a measure of beam size • Schedule

  9. Instrumentation and measurement techniques • X-ray beam size monitor at ATF DR, H.Sakai (Tokyo U.) • Fast X-ray beam size monitor for CesrTA, J.Alexander (Cornell U.) • High performance BPM, M.Wendt (FNAL) • AC dispersion measurement, D.Rubin (Cornell U.) • Beam based survey and alignemnt of magnets, D.Rubin (Cornell U.)

  10. Reports of machine experiences (tuning methods) • Coupling correction at Australian Synchrotron, R.Dowd (ASP) • PEP-II optics modeling and low emittance tuning, Y.Yan (SLAC) • Orbit response matrix analysis at ATF, A.Wolski (Cockcroft/U.Liverpool) • BBA at ATF, T.Okugi (KEK) • Optics correction at KEKB, K.Oide (KEK)

  11. Modeling and plans for future machines • NSLS-II Lattice design strategies, W.Guo (BNL) • Simulation of orbit and dispersion correction in ILC DR, K.Panagiotidis (Cockcroft)

  12. Modeling and plans for CesrTA • Optics modeling, D.Sagan (CLASSE) • Optics correction, D.Sagan (CLASSE) • Beam Based Alignment of BPM with Orbit Response Matrix and coupling measurement, J.Shanks (CLASSE) CLASSE: Cornell Laboratory for Accelerator Sciences and Education

  13. Our calibrated model indicates we can currently achieve a vertical emittance of ~ 2-3 pm.rad R.Dowd (ASP)

  14. C12 0, C22 = 0 C12 = 0, C22 0 Betatron Phase & Coupling Measurement Coupling and betatron phase and are measured by shaking the beam at a betatron resonance and looking at the response at the BPMs. y x General case: beam motion is elliptical y x y y x x David Sagan Cornell University No coupling case

  15. K.Oide • BPM has 4 electrodes. • x,y,intensity can be solved from data of 3 electrodes. • Can be used for gain calibration of the other electrode.  Drift of electronics can be corrected.

  16. For ATF, instrumentation • BPM performance is very important • 20 BPMs were upgraded for test and the performance confirmed • Remaining 76 BPMs ??? • Calibration should be regularly performed • Learn experience in KEKB (?) (man power) • Fast and accurate beam size monitor is important • Real time monitor during tuning • Possible “new” methods • AC measurement may be considered • Modulation of RF to induce synchrotron oscillation • Need turn by turn BPM • Resonance excitation (betatron oscillation) may be considered • Need phase lock of exciter, turn by turn BPM

  17. For ATF, tuning and correction • Optics should be cared. • Beta-function beats are very large. Need to perform matching. • Learn experiences of other rings. • Consider different COD, dispersion and Coupling correction methods (?)

  18. For ATF, alignment etc. • Magnet re-alignment will be done in this summer • Beam Based Alignment Measurement is important • Qaud to BPM is straight forward • Sext to BPM ? • Consider other methods. • Issues of skew quad • All sextpoles have skew quad trim coils. • Field quality has not been checked • Skew quad center is sext center ? (affect BBA)

  19. For ATF Low emittance, Summary Learn from other machines BPM performance is essentially important Continuous maintenance/ tuning/calibrations are important

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