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Beam Line Tuners (BLT) Overview for Enhanced Particle Beam Measurement and Control

This DoE Review discusses the functionality and operational status of Beam Line Tuners (BLTs), crucial in measuring transverse beam positions during transfers to optimize performance and enhance luminosity across the Tevatron and Main Injector. Emphasis is placed on improving betatron measurements and implementing feed-forward correction systems. The report covers system parameters, operational scopes, data acquisition advancements, and strategies for handling varying bunch formats, such as pbar and proton transfers. Key developments and future enhancements are outlined for ongoing effective beam management.

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Beam Line Tuners (BLT) Overview for Enhanced Particle Beam Measurement and Control

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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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