feedback on nanosecond timescales (font): philip burrows
DESCRIPTION
IP Feedback. Feedback On Nanosecond Timescales (FONT): Philip Burrows Neven Blaskovic, Douglas Bett, Glenn Christian, Michael Davis, Young Im Kim, Colin Perry John Adams Institute Oxford University. Outline. Reminder of CLIC IPFB prototype Remarks on L* ATF2 IP FB concept - PowerPoint PPT PresentationTRANSCRIPT
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Feedback On Nanosecond Timescales (FONT):
Philip Burrows
Neven Blaskovic, Douglas Bett, Glenn Christian, Michael Davis, Young Im Kim, Colin Perry
John Adams Institute
Oxford University
IP Feedback
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Outline
• Reminder of CLIC IPFB prototype
• Remarks on L*
• ATF2 IP FB concept
• Results of recent beam runs
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IP beam feedback concept
Last line of defence against relative beam misalignment
Measure vertical position of outgoing beam and hence beam-beam kick angle
Use fast amplifier and kicker to correct vertical position of beam incoming to IR
FONT – Feedback On Nanosecond Timescales
CLIC Final Doublet Region
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CLIC Final Doublet Region
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CLIC Final Doublet Region
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Comments on L*
• Current geometry:
time of flight IP BPM kicker IP ~ 24 ns
• Demonstrated FONT3 electronics latency = 13ns
• Estimated IPFB latency = 37ns
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CLIC IP FB performance
Single random seed of GM C
Resta Lopez
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For noisy sites:
CLIC IP FB performance
factor 2 - 3 improvement
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Comments on L*
• Current CDR geometry:
time of flight IP BPM kicker IP ~ 24 ns
• Demonstrated FONT3 electronics latency = 13ns
• Estimated IPFB latency = 37ns
• In principle, change of L* need not affect IPFB position and latency, but needs to be engineered carefully, considering other beamline components
CLIC Final Doublet Region
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FONT5 installation at ATF2
ATF2 extraction line
1212
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IP kicker IPBPMs
FONT digital
FB
IPBPMelectronics
FONTamplifier
e-
ATF2 IP FB loop scheme
Eventual goal is to stabilise the small ATF2 beam (design 37nm)at the nanometer level
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Nanometer beam FB at ATF2 IP
• Much harder than IPFB at ILC or CLIC!
• Only 1 beam must measure beam position directly
• nm-level stabilisation requires nm-level position meas.
Cavity BPMs (rather than striplines)
• Cavities intrinsically slow, signal processing complicated
• Cavities required to resolve 2 bunches within << 300ns
Low-Q cavities and low-latency signal processing
New BPMs+electronics (KNU), new IP chamber (LAL)
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Layout with new IP kicker
Designed by Oxford
Fabricationarrangedby KEK
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IP kicker IPBPMs
FONT digital
FB
IPBPMelectronics
FONTamplifier
e-
Preparatory tests June 2013
Existing IPBPMs
Honda low-latency electronics
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Preparatory test setup
A B
Preparatory test IPFB loop
Analogue Front-end
BPM processor
FPGA-based digital processor
Kicker drive amplifier
Strip-line kicker
Beam
Cavity BPM
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IP Feedback Results
FB Off Jitter: 170 ± 10 nmFB On Jitter: 93 ± 4 nm
FB Off Correlation: 81%
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IP Feedback Results
FB Off Jitter: 170 ± 10 nmFB On Jitter: 93 ± 4 nm
FB Off Correlation: 81%
FB On Correlation: -16%20
Incoming Beam Position Scan
10 μm pos. scan
Bunch 2
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IP BPM resolution
• Beam size during measurements ~ 100 nm
• Model beam jitter ~ 20% of beam size, i.e. 20nm
• Assuming results are resolution limited …
• Resolution = 93 nm / sqrt(2) ~ 65 nm
(no direct resolution measurement possible)
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New IP chamber installed summer 2013
Commissioning Started November:alignment, BPM signals
11cm Low-Q IP-BPM design
11cm Low-Q IP-BPM drawings of HFSS
100mm
100mm
Sensor cavity
Wave guideAntenna
Designed frequencyX-port: 5.712 GHzY-port: 6.426 GHz
Full size : 11cmx11cm (to
install IP-Chamber)Light weight:
1 kg (Single cavity)2 kg (Double cavity)
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In May tests resumed w. Honda electronics
FF quad current scan to set vertical beam waist at IPB
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In May tests resumed w. Honda electronics
Centre beam in BPM using mover optimise resolution
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In May tests resumed w. Honda electronics
Centre beam in BPM using mover optimise resolution
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Summary
• ATF2 IPFB prototype is progressing
• Beam stabilised (June 2013) to ~ 100nm level
• Beam jitters measured (June 2014) ~ 60nm (best)
• Beam studies continue until June 20th
• Attempting to disentangle jitter/resolution
• Looking at boosting signal levels resolution
• Hope to close FB loop with improved resolution