2008 FONT Report and Status Philip Burrows John

2008 FONT Report and Status Philip Burrows John Adams Institute Oxford University P. N. Burrows 1 ATF TB/SGC Meeting KEK 18/12/08

Feedback On Nanosecond Timescales Philip Burrows Glenn Christian Hamid Dabiri Khah Tony Hartin Javier Resta Lopez Colin Perry Graduate students: Christine Clarke Christina Swinson Ben Constance Robert Apsimon Douglas Bett SLAC, KEK, DESY, CERN P. N. Burrows 2 ATF TB/SGC Meeting KEK 18/12/08

FONT 4 ILC prototype at KEK/ATF Kicker BPM 1 e 1. 3 Ge. V Drive amplifier BPM 3 Analogue BPM processor 3 bunches, 140 -154 ns spacing Digital feedback P. N. Burrows BPM 2 3 ATF TB/SGC Meeting KEK 18/12/08

FONT 4 ILC prototype at KEK/ATF Kicker BPM 1 e- Drive amplifier BPM 2 BPM 3 Analogue BPM processor Digital feedback P. N. Burrows 4 ATF TB/SGC Meeting KEK 18/12/08

BPM processor 2005 P. N. Burrows 2006 5 2007 ATF TB/SGC Meeting KEK 18/12/08

Digital Feedback Board JTAG port PROM Xilinx Virtex 4 FPGA 40 MHz oscillator GP I/O Header Analog Devices ADC/DACs RS 232 comms 2 x Analog Output channels (differential) 4 x General-purpose digital outputs 2 x Analog Input channels (single-ended) P. N. Burrows 6 3 x external clock/trigger inputs ATF TB/SGC Meeting KEK 18/12/08

Kicker driver amplifier Specifications: • +- 15 A (kicker terminated with 50 Ohm) • +- 30 A (kicker shorted at far end) • 35 ns risetime (to 90%) • pulse length 10 us (specified for 20 -60 bunches) • repetition rate 10 Hz Outline design done in Oxford Order placed with TMD Technologies Sept 06 Two prototype units delivered Dec 06 Tested numerous times with beam in 2007 and 2008 Third unit delivered December 2008 P. N. Burrows 7 ATF TB/SGC Meeting KEK 18/12/08

Latency estimate • • Time of flight kicker – BPM: Signal return time BPM – kicker: Irreducible latency: 4 ns 10 ns 14 ns • • • BPM processor: ADC/DAC (3. 5 89 MHz cycles) Signal processing (9 357 MHz cycles) FPGA i/o Amplifier Kicker fill time Electronics latency: 10 ns 40 ns 28 ns 35 ns 3 ns 119 ns • Total latency budget: P. N. Burrows 133 ns 8 ATF TB/SGC Meeting KEK 18/12/08

FONT beamline section Amplifier P. N. Burrows FEATHER Kicker 9 BPM processor board ATF TB/SGC Meeting KEK 18/12/08

May 2008 Feedback Tests 1. Beam in fixed position: vary FB loop gain 2. Vary incoming beam position: optimise FB gain nominal +-150 um range around zero 3. Leave beam free-running and correct w. optimal gain • gain settings: 1000 (low), 1500 (medium), 1700 (high), 2000 (v. high) • Two modes of feedback: no delay loop, with delay loop • Data analysis in progress – all results preliminary! P. N. Burrows 10 ATF TB/SGC Meeting KEK 18/12/08

Example (1) of May 2008 Results low gain P. N. Burrows 11 ATF TB/SGC Meeting KEK 18/12/08

Example (1) of May 2008 Results low gain P. N. Burrows medium gain 12 ATF TB/SGC Meeting KEK 18/12/08

Example (1) of May 2008 Results low gain medium gain high gain P. N. Burrows 13 ATF TB/SGC Meeting KEK 18/12/08

Example (2) of May 2008 Results P. N. Burrows 14 ATF TB/SGC Meeting KEK 18/12/08

Example (2) of May 2008 Results P. N. Burrows 15 ATF TB/SGC Meeting KEK 18/12/08

Example (2) of May 2008 Results P. N. Burrows 16 ATF TB/SGC Meeting KEK 18/12/08

Example (3) of May 2008 Results P. N. Burrows 17 ATF TB/SGC Meeting KEK 18/12/08

Example (3) of May 2008 Results P. N. Burrows 18 ATF TB/SGC Meeting KEK 18/12/08

Latency measurement Bunch 1 Bunch 2 154 ns Latency Slack Kicker pulse Slack = 22 ns Latency = 154 - slack = 132 ns + 8 ns (1/Q)

FONT bench test system Manufacture synchronised ILC bunch-train, clocks, and trigger Develop algorithms and program FPGA Bunch Close loop Trigger 2. 16 MHz P. N. Burrows 20 Diagnostic ATF TB/SGC Meeting KEK 18/12/08

FONT plans (1) New ATF 2 beamline being commissioned Providing ‘turn-key’ bunch-by-bunch FB system for achievement of ATF 2 goals: 35 nm beam spot stabilisation at nanometer level at IP VITAL DEMONSTRATION OF FINAL-FOCUS CAPABILITY FOR ANY FUTURE LINEAR COLLIDER! P. N. Burrows 21 ATF TB/SGC Meeting KEK 18/12/08

ATF 2 FB system Dedicated system: • 2 stripline kickers + fast drive amplifiers • 3 stripline BPMs + fast analogue front-end electronics • 9 -channel digital FB processor P. N. Burrows 22 ATF TB/SGC Meeting KEK 18/12/08

ATF 2 FB system Dedicated system: • 2 stripline kickers + fast drive amplifiers • 3 stripline BPMs + fast analogue front-end electronics • 9 -channel digital FB processor P. N. Burrows 23 ATF TB/SGC Meeting KEK 18/12/08

ATF 2 FB system Dedicated system: • 2 stripline kickers + fast drive amplifiers • 3 stripline BPMs + fast analogue front-end electronics • 9 -channel digital FB processor P. N. Burrows 24 ATF TB/SGC Meeting KEK 18/12/08

Flexible FB / FF operation Time of flight P 2 -K 1 = 10. 7 ns Time of flight P 3 -K 2 = 10. 5 ns P. N. Burrows 25 ATF TB/SGC Meeting KEK 18/12/08

Results of vertical position correction Resta Lopez P. N. Burrows 26 ATF TB/SGC Meeting KEK 18/12/08

Status of FONT @ ATF 2 • • • 2 kickers (SLAC) ready 3 BPMs (KEK) ready Expect to install in beamline February 2009 3 amplifers (2 + spare) ready In progress: new 9 -channel digital FB board (improved BPM processors) • First tests Feb/March 2009 • Aim: system commissioned end 2009 P. N. Burrows 27 ATF TB/SGC Meeting KEK 18/12/08

FONT plans (2) The next major development would be FB tests using a long ILC-like train of 20 -60 bunches (FONT 4 amplifier was specified to allow this) • Would allow us to make FB algorithms robust: deal with bunch-bunch correlations along train adaptive gain as beam conditions change (drift) incorporate feed-forward information from upstream beam-related ‘luminosity’ signal for fast scanning? P. N. Burrows 28 ATF TB/SGC Meeting KEK 18/12/08