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Plans for FONT3 and Future Feedback Experiments. Philip Burrows Queen Mary, University of London ILC system overview FONT2 @ NLCTA: reminder FONT3/FEATHER plans at ATF Future feedback experiments. International Fast FB Collaboration. FONT:
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Plans for FONT3 and Future Feedback Experiments • Philip Burrows • Queen Mary, University of London • ILC system overview • FONT2 @ NLCTA: reminder • FONT3/FEATHER plans at ATF • Future feedback experiments Philip Burrows 2nd Nano Workshop, KEK 11/12/04
International Fast FB Collaboration • FONT: • Queen Mary: Philip Burrows, Glen White, Glenn Christian, • Hamid Dabirikhah, Tony Hartin, Stephen Molloy, Christine Clarke • Daresbury Lab: Alexander Kalinin, Roy Barlow, Mike Dufau • Oxford: Colin Perry, Gerald Myatt • SLAC: Joe Frisch, Tom Markiewicz, Marc Ross, Chris Adolphsen, Keith Jobe, Doug McCormick, Janice Nelson, Tonee Smith, Steve Smith, Mark Woodley • FEATHER: • KEK: Nicolas Delerue, Toshiaki Tauchi, Hitoshi Hayano • Tokyo Met. University: Takayuki Sumiyoshi, Fujimoto • Simulations: Nick Walker (DESY), Daniel Schulte (CERN) Philip Burrows 2nd Nano Workshop, KEK 11/12/04
Beam-based feedback in ILC • ‘Slow’ orbit (upstream BDS, linac) • Pulse-to-pulse (ILC: 5 Hz): extensive experience at SLC (120 Hz) • Intra-train (‘bunch-to-bunch’): • principal correction scheme in TESLA TDR • Integrated simulations linac -> IP + ground motion, wakefields … • (PLACET, LIAR, MERLIN, GUINEAPIG, CAIN) • Hardware prototyping of (fast analogue) critical components: • BPM processors, FB, drive amplifiers + closed-loop beam tests Philip Burrows 2nd Nano Workshop, KEK 11/12/04
Intra-train Beam-based Feedback • Intra-train beam feedback is last line of defence against relative beam misalignment • Key components: • Beam position monitor (BPM) • Signal processor • Fast driver amplifier • E.M. kicker • Fast FB circuit TESLA TDR: principal IR beam-misalignment correction Philip Burrows 2nd Nano Workshop, KEK 11/12/04
Zero-degree crossing angle (TESLA TDR) FB BPM Upstream kicker(s) Philip Burrows 2nd Nano Workshop, KEK 11/12/04
‘Large’ crossing angle (NLC) kicker FB BPM Philip Burrows 2nd Nano Workshop, KEK 11/12/04
Intra-train feedback performance (White/QMUL) OPTIMAL LUMINOSITY y angle scan y position scan: optimise signal in pair monitor (+4%) y position FB: restore collisions within 100 bunches 1 seed: post-BBA + GM + wakes Philip Burrows 2nd Nano Workshop, KEK 11/12/04
(FONT1 +) FONT2: beamline configuration Dipole and kickers BPMs Philip Burrows 2nd Nano Workshop, KEK 11/12/04
FONT1 + FONT2 amplifiers FONT1 3-stage tube amp FONT2 solid-state amp Up to 10A, 100V (x2) Up to 10A, 350V Bandwidth limited (30 MHz) Philip Burrows 2nd Nano Workshop, KEK 11/12/04
FONT2: expected latency • Time of flight kicker – BPM: 6ns • Signal return time BPM – kicker: 10ns • Irreducible latency: 16ns • BPM processor: 18ns • FB circuit: 4ns • Amplifier: 12ns • Kicker fill time: 3ns • Electronics latency: 37ns • Total latency expected: 53ns Philip Burrows 2nd Nano Workshop, KEK 11/12/04
FONT2 results: feedback BPM Beam starting positions beam start beam end Beam flattener on Feedback on 4 1 2 3 Delay loop on Philip Burrows 2nd Nano Workshop, KEK 11/12/04
FONT2 final results (Jan 22 2004) Super-fast modified configuration: Latency 54ns Correction 14:1 (limited by gain knob resolution) dispersion Philip Burrows 2nd Nano Workshop, KEK 11/12/04
FONT3 • Original aim: • Demonstrate micron-level stabilisation of 1.3 GeV ATF beam with latency c. 20 ns • EQUIVALENT TO: • nanometer stabilisation of 250-500 GeV LC beam with same lever arm … • -> demonstrate actual BPM processor and amplifier for warm LC • Worth completing, though low latency no longer critical Philip Burrows 2nd Nano Workshop, KEK 11/12/04
FONT3 outline Adjustable-gap kicker BPM ML11X BPM ML12X BPM ML13X Superfast amplifier Superfast BPM processor Aim: TOTAL latency < 20 ns Feedback Philip Burrows 2nd Nano Workshop, KEK 11/12/04
FONT3: latency budget • Time of flight kicker – BPM: 4ns • Signal return time BPM – kicker: 6ns • Irreducible latency: 10ns • BPM processor: 5ns • Amplifier + FB: 5ns • Electronics latency: 10ns • Total latency budget: 20ns • Will allow 56/20 = 2.8 periods during bunchtrain Philip Burrows 2nd Nano Workshop, KEK 11/12/04
FONT3: beamline configuration BPM ML11X kicker Philip Burrows 2nd Nano Workshop, KEK 11/12/04
FONT3 BPM processor (Molloy) • Latency budget 5ns • Superfast scheme: • down-mix to baseband • using 714 MHz LO • First tests June 2004 • Now testing improved • scheme w. different filter • options • Final version ready for • March 2005 Philip Burrows 2nd Nano Workshop, KEK 11/12/04
FONT3 amplifier (Perry) • Detailed design in progress • Tradeoff between drive and latency • latency < 5 ns constrains drive significantly • Lever-arm amplifier -> BPM very small: c. 1.1m • Solid state, low power ( < 100W) • Aiming for beam kick up to 20-30 microns at ML11X • First version will be tested in March 2005 • Slightly improved version possible for June 2005 Philip Burrows 2nd Nano Workshop, KEK 11/12/04
FONT3 DAQ/control (White) • Almost certainly use our 2 scopes (8 channels): • FB BPM output • drive signal to amplifier • 2 witness BPM y signals • Delay loop signal • 2 witness BPM y signals … • Auto control of corrector (ZV7X?) to produce controlled incoming beam offsets at FB BPM Philip Burrows 2nd Nano Workshop, KEK 11/12/04
FONT3 beam requirements • 20-bunch train (56 ns) • essential in order to see action of delay loop • Uniform charge within train (better than +- 10%) • essential since no time for charge normalisation • Flat bunch-bunch position profile within train • desirable • Small bunch-bunch position jitter within train (few microns) • essential • Small train-train jitter (few microns) essential to avoid amplifier saturation (c. 20 microns) Philip Burrows 2nd Nano Workshop, KEK 11/12/04
FONT3 jitter monitor (Kalinin) • Aim to measure bunch-bunch • jitter at micron level • First tests June 2005: • bunches resolved, but position • resolution > 10 microns • (common-mode rejection issues) • Improved processors being • tested now (BPMs 8, 10, 13) • + 2 BPMs in ring Philip Burrows 2nd Nano Workshop, KEK 11/12/04
Possible Future Experimental Programme (1) • Short-term: expect to finish FONT3 in June 2005 • Long-term: • demonstrate robust intra-train FB system for ILC, based on digital signal processing, and ideally test with beam: • requires long bunchtrain with 337 ns bunch spacing • > 2006 (?): 20 bunches x 337ns at ATF/ATF2 would be very attractive • 2005-6: 3 (or 4) bunches x 100 ns at ATF would also be interesting: • stabilise last bunch at 100 nm level as part of Nano project • also feed-forward studies ring -> extraction line? Philip Burrows 2nd Nano Workshop, KEK 11/12/04
2006: ‘Nano’ Project at KEK ATF FONT/FEATHER-style feed-forward and/or feedback Philip Burrows 2nd Nano Workshop, KEK 11/12/04
Possible Future Experimental Programme (2) • Study of performance of FB hardware in realistic IR environment: e+e- and gamma backgrounds • Make e+e- and gamma fluxes in SLAC A-line: • install BPM and study noise/long-term radiation effects • Concerns about EM pickup in FB BPM – test in IR mockup? • Intra-train beam feedback technology widely applicable: • emergency fast beam abort (DONT)? • beam position stabilisation for diagnostics: • laserwire, bunch-length monitor, Shintake monitor … Philip Burrows 2nd Nano Workshop, KEK 11/12/04