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Lesson from the Tevatron

Lesson from the Tevatron. Ron Moore Fermi National Accelerator Laboratory Accelerator Division / Tevatron Dept. Outline. Historical Highlights Luminosity Evolution of Collider Run 2 Reliability Upgrades and Other Issues Summary

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Lesson from the Tevatron

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  1. Lesson from the Tevatron Ron Moore Fermi National Accelerator Laboratory Accelerator Division / Tevatron Dept.

  2. Outline • Historical Highlights • Luminosity Evolution of Collider Run 2 • Reliability • Upgrades and Other Issues • Summary • Deliberately neglecting the Linac, Booster, Antiproton Source, Recycler – separate talks by themselves! R. Moore - FNAL

  3. Tevatron Operation Timeline • First Circulating Beam: 25 June 1983 • First 512 GeV Ramp with beam: 3 July 1983 • Fixed Target @ 800 GeV: 1983-1984 • First round of Tevatron dipole repairs (untied leads at interfaces) • First p-pbar Collisions: Oct 85 √s = 1.6 TeV • Collider Run 1: Aug 92 - Feb 96 √s = 1.8 TeV 6×6 • Linac upgrade and Tevatron cold-compressors during 93 shutdown • Fixed Target @ 800 GeV: Sep 96 - Sep 97, Jun 99 – Jan 00 • Main Injector installation between these runs • Collider Run 2: March 2001 – present √s = 1.96 TeV 36×36 ⇒The Tevatron was a mature machine when Run 2 began! R. Moore - FNAL

  4. Tevatron Run 2 Delivered Luminosity Approaching 5.5 fb-1 delivered Planned shutdowns R. Moore - FNAL

  5. >50 pb-1/week is common R. Moore - FNAL

  6. Tevatron Run 2 Initial Store Luminosity Each point is one store Recycler-only pbars & 28 cm β* R. Moore - FNAL

  7. Antiprotons Available for Tevatron Shot Factor 4-5 increase over Run 2 R. Moore - FNAL

  8. Luminosity Evolution • Tevatron luminosity increased mainly by increasing # of antiprotons and decreasing antiproton emittances • Antiproton production increases, electron cooling in Recycler • Also decreased β* from ≈40 cm to ≈28 cm in couple of steps • LHC luminosity evolution to be achieved mainly by increasing # of bunches and decreasing β* at the IPs • ≈200 E9/bunch should be straightforward • Tevatron typically has ≈270 E9 protons/bunch at HEP • Beam-beam effects • Tevatron already operating with head-on shift of ≈0.012 per IP • Early LHC @ ≈0.003 per IP, ultimately up to ≈0.012 (I believe) • Not uncharted territory for hadron collider • Beam-beam compensation techniques? (electron lens, wire…) R. Moore - FNAL

  9. R. Moore - FNAL

  10. Store Terminations Improving Reliability R. Moore - FNAL

  11. Upgrades after Run 2 Started • Additional separators • Increased beam separation → Improved luminosity lifetime • Improved instrumentation • New Schottky detectors for pbar tunes (design used for LHC system, too) • Faster Quench Protection Monitoring • 60 Hz → 5 kHz • Detect quench sooner, abort beam sooner • Beam Position Monitor (BPM) electronics • Resolution 100 → 10 µm • Improved lattice measurement, design, implementation • Automated orbit stabilization during stores • Better control store-to-store orbit changes • Beam Loss Monitor (BLM) electronics • Turn-by-turn capability • More flexible abort capabilities R. Moore - FNAL

  12. Other Issues Discovered in Run 2 • Large coupling – need to reshim cryostat supports in every dipole • G11 shims compressed over time, cryostat sunk ~1 mm within iron • Reshimmed all Tevatron dipoles over 3 long shutdown periods • CDF was sinking ~1mm/yr early in Run 2 • Lowered/aligned low-β quad girders during shutdowns to adjust IP • Still few mm below rest of Tevatron – aperture, steering complications • Relatively fast low-β quad motion at CDF and D0 • Collision hall HVAC and air flow between halls and Tevatron • Changes orbits, tunes, losses during HEP stores • Orbit stabilization, insulation around quad girders mitigate • Magnet realignment campaign • Unroll typically 50-60 magnets < 1 mrad every long shutdown R. Moore - FNAL

  13. Hindsight and a Look to the Future "It works! This is by far the most significant thing that can be said in retrospect. One tends to forget that it was not obvious that the Energy Doubler would work and the years of effort with many failures and setbacks that went into the magnet and cryogenic development. There are no major flaws in the system that we know of to date, but one should keep in mind that it is very much a prototype accelerator. It is as much an accelerator research tool as a high-energy physics tool. It will take time for the performance to become as dependable as expected from conventional accelerators." - Helen Edwards, “The Tevatron Energy Doubler: A Superconducting Accelerator”, Ann. Rev. Nuclear Part. Sci. 1985, Vol. 35 (605-660). R. Moore - FNAL

  14. Summary • When extrapolating Tevatron experience to LHC, consider: • Tevatron already mature at start of Collider Run 2 • Antiproton improvements big role in Tevatron luminosity evolution • Improving uptime and operational stability still continue • LHC needs to establish its operational reliability to gain confidence in integrated luminosity projections • How many store hours per week? • Expect the unexpected • Although peak luminosity is important (especially when discussing upgrades), maximizing integrated luminosity on tape is the ultimate goal R. Moore - FNAL

  15. Backup Slides R. Moore - FNAL

  16. Hindsight and a Look to the Future (2) "The overriding issue for the next generation of large superconducting accelerators-colliders must be reliability. Some real assessment of the probable success in meeting operating goals must be made, and large prototype systems tested for fatal flaws. The reliability issue must be treated with a care it never has received in past accelerators." - Helen Edwards, “The Tevatron Energy Doubler: A Superconducting Accelerator”, Ann. Rev. Nuclear Part. Sci. 1985, Vol. 35 (605-660). R. Moore - FNAL

  17. (since Oct 2007) R. Moore - FNAL

  18. Store Terminations R. Moore - FNAL

  19. Tevatron Run 2 Delivered Luminosity R. Moore - FNAL

  20. NuMI (120 GeV) MiniBoone (8 GeV) A1 Line P1 Line

  21. Tevatron Dipole 6.4 m long 4.5 T operating B field Provides ~8 mrad bend 770 dipoles in Tevatron

  22. Tevatron Dipole in Cross-Section R. Moore - FNAL

  23. Destroyed Collimators in Tevatron stored beam energy 1013 protons @ 1 TeV ≈ 1.6 MJ Damage done in ~10 ms Protons tungsten 1.5 m long stainless steel Motivation for improving quench protection system R. Moore - FNAL

  24. Magnet Motion / Orbit Stabilization New BPM electronics help us see this motion! E11 vert BPM [mm] Orbit stabilization ON F17 horz BPM [mm] Proton vert tune D0 proton halo [Hz] C4Q4 roll [μrad] C4Q4 pitch [μrad] Proton intensity [E9] V. Ranjbar Store 4402 R. Moore - FNAL

  25. Looking Down on the Fermilab Accelerator Complex Wilson Hall Main Injector CDF Tevatron 1 km Try this link:Fermilab from Google Maps D0

  26. In the Tevatron Tunnel R. Moore - FNAL

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