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Feedback On Nanosecond Timescales

Feedback On Nanosecond Timescales. Philip Burrows Glenn Christian Hamid Dabiri Khah Javier Resta Lopez Colin Perry Graduate students: Christina Swinson Ben Constance Robert Apsimon Douglas Bett Alexander Gerbershagen Angeles Faus Golfe Javier Alabau CERN, DESY, KEK, SLAC.

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Feedback On Nanosecond Timescales

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  1. Feedback On Nanosecond Timescales • Philip Burrows • Glenn Christian • Hamid Dabiri Khah • Javier Resta Lopez • Colin Perry • Graduate students: • Christina Swinson • Ben Constance • Robert Apsimon • Douglas Bett • Alexander Gerbershagen • Angeles Faus Golfe • Javier Alabau • CERN, DESY, KEK, SLAC P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  2. FONT4/5 prototypes at KEK/ATF2 Kicker BPM 1 BPM 2 BPM 3 e- 1.3 GeV Drive amplifier Analogue BPM processor 3 bunches, 140-154ns spacing Digital feedback P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  3. FONT4 prototype at KEK/ATF Kicker BPM 1 BPM 2 BPM 3 e- Drive amplifier Analogue BPM processor Digital feedback P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  4. BPM processor 2007 2005 2006 P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  5. Digital Feedback Board JTAG port PROM Xilinx Virtex4 FPGA 40 MHz oscillator GP I/O Header Analog Devices ADC/DACs RS232 comms 2 x Analog Output channels (differential) 4 x General-purpose digital outputs 2 x Analog Input channels (single-ended) 3 x external clock/trigger inputs P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  6. Kicker driver amplifier • Specifications: • +- 15A (kicker terminated with 50 Ohm) • +- 30A (kicker shorted at far end) • 35ns risetime (to 90%) • pulse length 10 us (specified for 20-60 bunches) • repetition rate 10 Hz • Outline design done in Oxford • CASE studentship w TMD Technologies • Order placed with TMD Sept 06 • Two prototype units delivered Dec 06 • 2 units in service at KEK since 2007 • (2009: upgrades made + 1 unit) P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  7. FONT4 status • FONT4 basic operation demonstrated in 2008 running: • beam feedback along single axis (y) with few micron resolution P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  8. FONT4 status • FONT4 basic operation demonstrated in 2008 running: • beam feedback along single axis (y) with few micron resolution P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  9. FONT operations in 2009 • FONT4 installation was dismantled when ATF extraction line was reconfigured late 2008 P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  10. ATF2 FB system: FONT5 • Dedicated • system: • 2 stripline • kickers + • fast drive amplifiers • 3 stripline BPMs + • fast analogue front-end electronics • 9-channel digital FB processor P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  11. ATF2 FB system: FONT5 • Dedicated • system: • 2 stripline • kickers + • fast drive amplifiers • 3 stripline BPMs + • fast analogue front-end electronics • 9-channel digital FB processor P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  12. ATF2 FB system: FONT5 • Dedicated • system: • 2 stripline • kickers + • fast drive amplifiers • 3 stripline BPMs + • fast analogue front-end electronics • 9-channel digital FB processor P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  13. FONT5 operations in 2009 • FONT4 installation was dismantled when ATF extraction line was reconfigured late 2008 • 3 new BPMs and 2 new kickers installed in new ATF2 extraction line week of February 9 P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  14. New FONT5 ATF2 hardware P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  15. FONT5: Jan-May 2009 • FONT4 installation was dismantled when ATF extraction line was reconfigured late 2008 • 3 new BPMs and 2 new kickers installed in new ATF2 extraction line week of February 9 • Main aims: • 1) commission new BPMs and kickers (digital DAQ) • 2) work on improved resolution  1 um level • 3) understand beam dynamics in FONT region • Much commissioning work done parasitically - now have FONT ‘standalone’ hardware • We typically took 1 shift per week March - May, a total of 6 shifts (!) P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  16. Example: BPM calibrations P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  17. Example: kicker calibration Kick of +-40 urad 6

  18. Example: resolution vs. bunch Q P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  19. Phase stability of 357 vs. 714 MHz • We take 714 MHz signal from machine as LO signal for down-mixing of BPM signals • Frequency divide 714 MHz to obtain 357 MHz for clocking the FONT digital FB board • We observed phase jumps between 357 and 714 MHz signals P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  20. Phase difference of 714 and 357 MHz signals Phase jumps P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  21. Phase stability of 357 vs. 714 MHz • We take 714 MHz signal from machine as LO signal for down-mixing of BPM signals • Frequency divide 714 MHz to obtain 357 MHz for clocking the FONT digital FB board • We observed phase jumps between 357 and 714 MHz signals • A 180-degree shift of 357 MHz would cause ADC sample to miss beam by 2.8ns  reduce signal by up to 50% • We tried ‘stable’ source of 714 MHz derived from frequency generator phase-locked to master oscillator P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  22. Comparison of ‘stable’ and ‘unstable’ 714 MHz P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  23. FONT5 since June 2009 • New FONT5 9-channel FB/FF board (y, y’) assembled (Sept. 2009) • Bench tested in Oxford (October) • Sent to KEK (November) for beam tests • Shipped back and repaired (1 week turnaround) • Now undergoing further beam tests • looks very promising P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  24. Single bunch calibration: November 19 24 P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  25. Single bunch calibration: P3 problem November May 25 P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  26. P3 problem • Bottom stripline had 20 db lower response • Pickup removed from beamline and examined during November down week • Lot of dust found inside! • Noticed that bottom electrode closer to BPM housing than other electrodes – fabrication error? • BPM rotated by 90 degrees and reinstalled • Will be replaced in December shutdown • BPM had been removed in summer for welding of bellows: probably rotated by 90 degrees then P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  27. ZV6X corrector setting: May

  28. ZV6X corrector setting: November

  29. FB loop closed on on off off Ben Constance 27th November 2009 2

  30. Interleaved FB on/off mode 27th November 2009

  31. Interleaved FB on/off mode 1 off/on 27th November 2009

  32. Interleaved FB on/off mode 2 off 1 off/on 27th November 2009

  33. Interleaved FB on/off mode 2 on 2 off 1 off/on 27th November 2009

  34. Interleaved FB on/off mode 2 on 3 off 2 off 1 off/on 27th November 2009

  35. Interleaved FB on/off mode 3 on 2 on 3 off 2 off 1 off/on 27th November 2009

  36. FB loop closed on on off off Ben Constance 27th November 2009 2

  37. Beam issues • Banana-shaped train • studies to see if train can be extracted flat • ‘flattening’ signal implemented in firmware • Significant bunch-bunch jitter within train • Bunches 1 and 3 typically poorly correlated • studies to understand origin of decorrelations P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  38. Extraction kicker timing studies

  39. Beam jitter/correlation studies18 November 2009, Std Optics, 3 train, 151.2 ns BS (with FONT4 electronics, P1 & P2 only)‏ Mean position and RMS jitter at P2: Bunch1: 68.9 +/- 5.1 um Bunch2: 59.4 +/- 4.7 um Bunch3: 46.3 +/ 5.0 um RMS sagitta wrt train mean: 11.3 um Bunch-to-bunch correlations at P2: B1/B2: 0.76 B2/B3: 0.77 B1/B3: 0.78 resolution < 2.3 um, based on jitter and correlation observed. P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  40. Beam jitter/correlation studies11 December 2009, Std Optics, 3 train, 151.2 ns BS (with FONT5 electronics - P1, P2, & P3)‏ Mean position and RMS jitter at P2: Bunch1: -91.7 +/- 18.4 um Bunch2: -80.9 +/- 16.7 um Bunch3: -91.3 +/ 15.7 um RMS sagitta wrt train mean: 6.1 um Bunch-to-bunch correlations at P2: B1/B2: 0.48 B2/B3: 0.75 B1/B3: -0.02 (non sign.)‏ 3-BPM resolution estimates: B1: 3.9 um, B2: 3.3 um, B3 3.4 um P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  41. Beam jitter/correlation studies11 December 2009, Std Optics, 3 train, 151.2 ns BS, AFTER DR CHROMATICITY CORRECTION Mean position and RMS jitter at P2: Bunch1: -90.7 +/- 15.1 um Bunch2: -82.6 +/- 14.3 um Bunch3: -94.6 +/ 17.0 um RMS sagitta wrt train mean: 6.1 um Bunch-to-bunch correlations at P2: B1/B2: 0.42 (non sign.)‏ B2/B3: 0.60 B1/B3: -0.07 (non sign.)‏ 3-BPM resolution estimates (low stats): B1: 3.6um, B2: 2.9 um, B3: 2.8 um P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  42. Bunch correlations vs. DR RF scan11 December 2009, Std Optics, 3 train, 151.2 ns BS, ~50 pulses/setting P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  43. Bunch correlations vs. beam charge11 December 2009, Std Optics, 3 train, 151.2 ns BS, ~100 pulses/setting P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  44. FONT5 summary 2009 • New BPMs and kickers installed + working • FONT5 FB board fabricated and commissioned • FB loop closed • Beam quality is a serious issue: • banana-train can be tuned away (or corrected) • large jitter and • lack of correlation between bunches are major • problems • (sometimes jitter is small and well correlated!) • THIS WILL NOT BE BETTER WITH 30 BUNCHES! P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  45. Valencia Movers P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  46. +- 2.5 mm horizontal +- 2mm vertical P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

  47. FONT plans: 2010 • Install Valencia movers (January) • Provide ‘turn-key’ bunch-by-bunch FB system for • achievement of ATF2 goals • Plan to replace LO-based BPM processor scheme P.N. Burrows ATF2 Project Meeting, KEK, 14/12/09

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