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Beam Line Tuners

Beam Line Tuners. Vic Scarpine Instrumentation DoE Review Oct 28-31, 2002. Introduction. Primary function of a Beam Line Tuner (BLT) is to measure turn-by-turn transverse beam positions during transfers between machines at injection to improve closing

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Beam Line Tuners

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  1. Beam Line Tuners Vic Scarpine Instrumentation DoE Review Oct 28-31, 2002

  2. Introduction • Primary function of a Beam Line Tuner (BLT) is to measure turn-by-turn transverse beam positions during transfers between machines at injection to improve closing • Required in Tevatron, Main injector and Recycler • Can measure betatron oscillations, fractional tune, coupling, phase, synchrotron oscillations, chromaticities, etc • Focus has been on betatron measurements for improved closing • Feed-forward correction system • BLT is a key component for reducing transverse emittances and increase luminosity DoE Review - Instrumentation - BLT

  3. Basic BLT System DoE Review - Instrumentation - BLT

  4. Striplines and Fanout TeV Stripline Parameters: • ~ 30 dB directionality • 1 meter long (< 1/4 l) • D = 83 mm • 0.65 dB/mm Sensitivity MI and Recycler Stripline Parameters: • Unidirectional • 1.4 meter long (1/4 l) • D = 110 mm • 0.50 dB/mm Sensitivity DoE Review - Instrumentation - BLT

  5. Operational Systems DoE Review - Instrumentation - BLT

  6. Tevatron BLT • For transfers from Main Injector to Tevatron • Requirements (in order of importance – V. Lebedev): • Measure initial injection oscillations for every proton and pbar bunch • first 50 turns with <50 mm resolution • Measure tunes, coupling and chromaticities for every bunch • > ~1000 turns • Monitor beam position before quench • ~ last 500 turns saving beam waveforms • Beam formats: • Pbar: • Four 53 MHz bunches separated by 392 ns at 150 GeV • Protons: • Single 53 MHz bunch at 150 GeV DoE Review - Instrumentation - BLT

  7. Tevatron Scope BLT • In Operations • Use Tektronix TDS7104 as fast waveform digitizer • 2.5 GSample/sec/channel • Segmented memory • Embedded Celeron PC • Samples proton bunch or four pbar bunches per transfer • Signal processing analysis on waveform in Scope PC • Decimate data to single position per bunch • Pbars – 64 turns • Protons – 256 turns DoE Review - Instrumentation - BLT

  8. Tevatron Scope BLT Results 4 pbar bunches per transfer; 64 turns per bunch; closing on second bunch 1 2 3 4 1 2 3 4 First Pbar Transfer Sixth Pbar Transfer DoE Review - Instrumentation - BLT

  9. Tevatron Scope BLT • Position calculation: X = K * (A – B) / (A + B) Resolution: ~ 140 mm • Calculate oscillation phase and amplitude from first 16 turns • Correct injection magnets for next transfer for amplitudes > 0.25 mm Betatron phase and amplitude for all 36 pbar bunches DoE Review - Instrumentation - BLT

  10. Tevatron Scope BLT Status • Tektronix scope system in operations • Limited by slow internal data transfer • ~20 seconds for 64 turns for pbars • Improvements • New scopes have increased memory – two scopes just arrived • Allows for ~800 turns for pbars, ~2000 turns for protons • Upgrade scope software to improve internal data transfer • Increase acquisition speed by ~ x10 • Modifying position algorithm to improve resolution • ~ 30 to 50 mm • Integrate improvements over next few weeks DoE Review - Instrumentation - BLT

  11. Main Injector BLT Requirements: • Measure position for first 1024 turns for all pbar bunches at injection from either Accumulator or Recycler • “Hot” pbars from Tevatron in future Beam Formats: • Accumulator to Main Injector – Four batches of 7 to 13 bunches of 53 MHz at 8 GeV • Recycler to Main Injector – Four bunches at 2.5 MHz at 8 GeV • Tevatron to Main Injector – 36 single bunches at 53 MHz at 150 GeV (Hot pbars) DoE Review - Instrumentation - BLT

  12. Main Injector BLT in Operations • Using older AM/PM modules (see J. Crisp talk on BPMs) • Originally designed for eighty-four 53 MHz bunches • Lower efficiency for 7 bunches • Less resolution • Won’t work for 2.5 MHz • Digitize at 53 MHz • LabView controls acquisition and analysis • Output 1024 vertical and horizontal positions plus fractional tunes and betatron phase and amplitude to ACNET DoE Review - Instrumentation - BLT

  13. Main Injector BLT Results • Positions and tunes for first 1024 turns • Correct on second bunch in transfer • Phase and amplitude for 9 transfers • Correct for amplitude > 0.5 mm DoE Review - Instrumentation - BLT

  14. Main Injector BLT Status • Present system based on old AM/PM modules • Adequate for closing but needs updated to more responsive system • System can not measure 2.5 MHz beam from Recycler Plan: • Installing Digital Receiver system for 2.5 MHz beam • Installation occurring now • Need to replace present 53 MHz system • Decision to be made on choice of Digital Receiver system or Scope system DoE Review - Instrumentation - BLT

  15. Recycler BLT • Requirements: • Measure position for first 1024 turns for all bunches at injection from Main Injector to Recycler • Waveforms: • Four 2.5 MHz pbar bunches at 8 GeV • System based on Digital Receiver technology • Uses Echotek digital receiver • Just into Operations DoE Review - Instrumentation - BLT

  16. Digital Receiver Options • Hardware Option (see J. Crisp talk on BPMs) • 8 channel EchoTek card (VME64) • 65 MHz ADC, 14 bits • Hardware digital mixer, filters and decimation • Software Option • 8 channel Struck digitizer (VXI) • 100 MHz ADC, 12 bits • Software digital mixer • Correlation algorithm to measure channel amplitude DoE Review - Instrumentation - BLT

  17. Recycler BLT Positions and tunes for 1024 turns DoE Review - Instrumentation - BLT

  18. Recycler BLT Status • System in operations for about one week • Closing routinely to < 0.3 mm • No changes planned to system DoE Review - Instrumentation - BLT

  19. Systems in Development DoE Review - Instrumentation - BLT

  20. TeV Scope BLT Phase Detector • Measures phase of four pbar bunches relative to RF using Tektronix 7104 scope • Measurement point every 18 turns • 64 turns is really 1100 turns • Phase error of ~11 degrees (~0.55 ns) • Resolution ~ 1 degree (50 ps) 1 2 3 4 DoE Review - Instrumentation - BLT

  21. Tevatron Digital Receiver BLT Software version of Digital Receiver system for pbars • 30 MHz LP to ring single 53 MHz bunch • Ring for ~100 ns • Digitize at 100 MHz • Correlate with normalized response function • Generate position and bunch phase for >1024 turns DoE Review - Instrumentation - BLT

  22. TeV Digital Receiver BLT Horizontal Tunes Vertical Tunes DoE Review - Instrumentation - BLT

  23. TeV Digital Receiver BLT Vertical Position vs Turn Horizontal Position vs Turn DoE Review - Instrumentation - BLT

  24. TeV Digital Receiver BLT Comparison of position data to theory (courtesy of V. Lebedev) + Horizontal Position, --- Difference from fit Position, --- Difference from fit Synchrotron factored out DoE Review - Instrumentation - BLT

  25. Tevatron Waveform Movie Proton injection Vertical Stripline into fast scope • Red = A-B • Blue = A+B • 1 to 2000 turns by 20 • 0.5 ns sampling • Negative Vertical Chromaticity • Longitudinal dampers off DoE Review - Instrumentation - BLT

  26. Head-Tail Measurements(courtesy of P. Ivanov) Developing of the head-tail instability with dipole longitudinal configuration Developing of the head-tail instability with monopole longitudinal configuration DoE Review - Instrumentation - BLT

  27. Chromaticity Measurement by the Head-Tail Monitor(courtesy of P. Ivanov) DoE Review - Instrumentation - BLT

  28. Summary • Tevatron, Main Injector 53MHz and Recycler 2.5 MHz operational for injection closing • Main Injector 2.5 MHz being installed • Upgrades progressing for Tevatron and Main Injector 53 MHz systems • Multi-systems need to be evaluated and decision made on priorities and how many systems to support • Advantages and disadvantages of each system • Need to guard against over design DoE Review - Instrumentation - BLT

  29. Cast of Characters Instrumentation: Jim Crisp, Brian Fellenz, Eugene Lorman, Warren Schappert Pbar Source: Dave McGinnis Tevatron: Petr Ivanov, Valeri Lebedev Advise and Consent: Church, Pasquinelli, Pordes and others …with apologies to anyone forgotten DoE Review - Instrumentation - BLT

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