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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 20081 Philip Burrows John Adams Institute Oxford University G. Christian, C. Clarke, B. Constance, H. Dabiri Khah, T. Hartin, C. Perry, C. Swinson John Adams Institute, Oxford University A. Kalinin, Daresbury Laboratory R. Arnold, S. Molloy, S. Smith, G.R. White, M. Woods, SLAC Electromagnetic Background Tests for the Interaction Point Feedback System
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 20082 Outline Introduction ILC interaction point intra-train feedback system Beam-beam interaction and EM backgrounds T488 experiment at SLAC Endstation A Conclusions
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 20083 Intra-train feedback system - 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 incoming beam FONT: Feedback On Nanosecond Timescales IP
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 20084 KickerBPM 1 Digital feedback Analogue BPM processor Drive amplifier BPM 2 BPM 3 e- FONT4 prototype at KEK/ATF
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 20085 KickerBPM 1 Digital feedback Analogue BPM processor Drive amplifier BPM 2 BPM 3 e- FONT4 prototype at KEK/ATF Latency ~ 140ns
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 20086 Reminder of FB performance 154ns FB off FB on ‘banana’ effectcorrected! Beam Position (ADC counts)
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 20087 154ns FB off FB on ‘banana’ effectcorrected! Beam Position (ADC counts) With 1/Q + optimised gain Reminder of FB performance
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 20088 ILC interaction region (schematic)
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 20089 Nominal IP feedback BPM location BPM (stripline)
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 200810 Pair-induced EM backgrounds BPM e+e- pairs Low-Z mask + beamline calorimeter
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 200811 Backgrounds due to e+e- pairs Beam Parameters SchemeNumber of Pair ParticlesAverage Energy (GeV)BPM hits Scheme 1 19565210.85141 Scheme 2 16437010.62894497 Scheme 3 12196610.89473057 Scheme 4 4972012.34211074 Scheme 5 1242739.583012321 Scheme 6 27221810.66369686 Scheme 7 32035210.980912314 Scheme 8 19316611.28265127 Scheme 9 23774911.53178758 Scheme 10 19297611.30836399 Scheme 11 8521812.80342623 Scheme 12 24768310.12129287 Scheme 13 50045713.854925016 Scheme 14 67881115.584580443
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 200812 Backgrounds due to e+e- pairs Beam Parameters SchemeNumber of Pair ParticlesAverage Energy (GeV)BPM hits Scheme 1 19565210.85141 Scheme 2 16437010.62894497 Scheme 3 12196610.89473057 Scheme 4 4972012.34211074 Scheme 5 1242739.583012321 Scheme 6 27221810.66369686 Scheme 7 32035210.980912314 Scheme 8 19316611.28265127 Scheme 9 23774911.53178758 Scheme 10 19297611.30836399 Scheme 11 8521812.80342623 Scheme 12 24768310.12129287 Scheme 13 50045713.854925016 Scheme 14 67881115.584580443 Parameter space for 500 GeV ILC Parameter space for 1 TeV ILC
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 200813 Backgrounds due to e+e- pairs Beam Parameters SchemeNumber of Pair ParticlesAverage Energy (GeV)BPM hits Scheme 1 19565210.85141 Scheme 2 16437010.62894497 Scheme 3 12196610.89473057 Scheme 4 4972012.34211074 Scheme 5 1242739.583012321 Scheme 6 27221810.66369686 Scheme 7 32035210.980912314 Scheme 8 19316611.28265127 Scheme 9 23774911.53178758 Scheme 10 19297611.30836399 Scheme 11 8521812.80342623 Scheme 12 24768310.12129287 Scheme 13 50045713.854925016 Scheme 14 67881115.584580443 Primaries per bunch crossing: 50 – 700k
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 200814 Backgrounds due to e+e- pairs Beam Parameters SchemeNumber of Pair ParticlesAverage Energy (GeV)BPM hits Scheme 1 19565210.85141 Scheme 2 16437010.62894497 Scheme 3 12196610.89473057 Scheme 4 4972012.34211074 Scheme 5 1242739.583012321 Scheme 6 27221810.66369686 Scheme 7 32035210.980912314 Scheme 8 19316611.28265127 Scheme 9 23774911.53178758 Scheme 10 19297611.30836399 Scheme 11 8521812.80342623 Scheme 12 24768310.12129287 Scheme 13 50045713.854925016 Scheme 14 67881115.584580443 BPM hits per bunch crossing: 1 – 80k
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 200815 Pair-induced EM backgrounds BPM e+e- pairs Low-Z mask + beamline calorimeter
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 200816 FONT Test Module for ESA low Z mask beamcal BPM QFEX1 Material model of ILC outgoing beamline
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 200817 FONT Test Module (T-488) Installation at ESA Beam
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 200818 Overview of T-488 Experiment Used 28.5 GeV SLAC beam to simulate ILC EM background environment: Mode 1: Large beam ~ 1mm diameter, 10**6 < Q < 10**8 Beam steered onto front of FONT module Mode 2: Beam passed through upstream thin radiator Main beam + halo that strikes module
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 200819 Used 28.5 GeV SLAC beam to simulate ILC EM background environment: Mode 1: Lose primary beam signal in BPM Vary noise signal at BPM by varying Q Mode 2: Still get primary beam signal in BPM Tune noise signal at BPM by varying X0 Studied impact on stripline BPM signals Overview of T-488 Experiment
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 200820 Mode 1: beam scan across module: stripline BPM signals 10**7 beam
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 200821 10**7 beam Mode 1: beam scan across module: stripline BPM signals
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 200822 10**7 beam Mode 1: beam scan across module: stripline BPM signals
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 200823 Noticeable degradation of signals 10**7 beam Mode 1: beam scan across module: stripline BPM signals
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 200824 Modelling of noise on BPM strips
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 200825 Modelling of noise on BPM strips data simulation
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 200826 Mode 2: primary beam + halo 12 metres Thin foil (0.3 mm -1.5 mm)The module Scaling from ESA to ILC: ESA ILC Beam halo
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 200827 Mode 2: results: worst case: 5% foil foil in foil out in vs. out
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 200828 Peak voltages foil in vs foil out Foil thicknessFoil INFoil OUT Mean / Vstd / VMean / Vstd / V 5%3.990.094.000.09 3%4.000.08 1%3.990.094.010.09 See no effect within statistics (1000 pulses) < 10 micron effect in position at ESA < 100 nm at ILC c.f. FB BPM resolution needed ~ few microns
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Philip Burrows ECFA LC Workshop, Warsaw, 10 June 200829 Summary + conclusions EM backgrounds were source of concern for operation of a feedback BPM in ILC interaction region Built a material model of ILC extraction line Used SLAC/ESA 28.5 GeV beam to simulate ILC EM bgds Developed simple BPM noise model; reproduces data Under background conditions c. 1000 x worse than ILC we saw no degradation of BPM operation < 100nm degradation in resolution at ILC -> current design of IP FB system looks robust
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