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Review of Recent Tevatron Operations

Review of Recent Tevatron Operations. Ron Moore Fermilab – Tevatron Dept. Overview. Tevatron 1 km radius superconducting synchrotron at 980 GeV beam energy Tevatron 36 ×36 proton-antiproton collisions to CDF & D0 experiments 3 trains of 12 bunches each with 396 ns separation

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Review of Recent Tevatron Operations

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  1. Review of RecentTevatron Operations Ron Moore Fermilab – Tevatron Dept.

  2. Overview • Tevatron • 1 km radius superconducting synchrotron at 980 GeV beam energy • Tevatron 36×36 proton-antiproton collisions to CDF & D0 experiments • 3 trains of 12 bunches each with 396 ns separation • Protons and antiprotons circulate in single beam pipe • Electrostatic separators keep beams apart except where/when desired • Beam-beam interactions (head-on & long range) play major role R. Moore - FNAL

  3. Tevatron Delivered Luminosity > 1.5 fb-1 since June 2006 R. Moore - FNAL

  4. Tevatron Run 2 Peak Luminosities Recycler-only pbars & 28 cm β* R. Moore - FNAL

  5. 2006 Tevatron Shutdown Tasks • Fixed known cold leaks in E2, A3, B4; replace failed dipole in F4 • Installed 2 new separators (B48, A17), replace 3 separators (A49) • Completed reshimming on remaining 228 dipoles • Replaced all ≈1200 helium relief valves (Kautzky) on magnets • Repaired TEL-1 and installed TEL-2 (electron lenses) • Pulled cables for new sextupole circuits (2nd order chromaticity correction) • Unrolled quads in A3 (~10 mrad); unroll ~60 magnets with small rolls • Completed IPM detector installation • Completed ring-wide hydrostatic level sensor installation • Many smaller tasks, lots of maintenance… • Tevatron Run II upgrades effectively complete! R. Moore - FNAL

  6. Highlights since 2006 shutdown… • Record delivered luminosity / week 24.4 → 44.9 pb-1 • Record peak luminosity 180 → 292 1030 cm-2 s-1 • Delivered > 1.5 fb-1 to CDF and D0 (Run 2 total delivered now > 3 fb-1) • More antiprotons with smaller emittances to HEP • Thanks to Antiproton Source and Recycler • See K. Gollwitzer’s talk tomorrow afternoon (WEZAKIO1) • More protons to HEP • Injecting ≈10% more protons • Better lifetime @ 150 GeV from new helical orbit, reduced beam-beam • Improved luminosity lifetime • Additional separators increase separation (up to 20% at parasitic crossings) • Beam-beam effects reduced • Commissioned TEL-2 and demonstrated beam-beam compensation on protons • See V. Shiltsev’s talk later this session (TUOCKI04) R. Moore - FNAL

  7. 2006 shutdown Beam Intensities in HEP Stores 9500 E9 ≈ 264 E9 / bunch 3000 E9 ≈ 83 E9 / bunch R. Moore - FNAL

  8. Improved Proton Efficiency vs Pbar Intensity New injection helix increased separation between beams  reduced beam-beam effects R. Moore - FNAL

  9. Larger Separation with New Collision Helix • Installed 2 additional separators during 2006 shutdown • Luminosity lifetime improved ~20% compared to pre-shutdown • Increased integrated luminosity per store (for similar luminosities and duration) Beam separation in σ blue – oldred – present Distance from B0 [m] R. Moore - FNAL

  10. Better Lifetime  More Delivered Luminosity Based on luminosity lifetime fits and adjusting to 24 hour store duration R. Moore - FNAL

  11. Beam Lifetimes during HEP • Pbar lifetime dominated by luminosity – good • Most protons lost in non-luminous processes – not so good • Head-on beam-beam effects from smaller emittance pbars on protons 300 225 150 75 0 Store 5245 Luminosity [μb-1/s] Pbar Lifetime / ExpectedLifetime from Luminosity 1 0.75 0.5 0.25 0 Proton Lifetime / ExpectedLifetime from Luminosity R. Moore - FNAL

  12. Store 5245 – Comparison to Model w/o Beam-Beam Luminosity Integral Model Data Initial Lumi = 286 μb-1/s ~10% luminosity loss from beam-beam effects See A. Valishev’s talk later this sesssion (TUOCKI03) R. Moore - FNAL

  13. Reliability • Over 280 HEP stores since June 2006 – 75% terminated intentionally • Slightly better than the 72% Run 2 historical average • Causes: power supplies ≈ 24%, cryo ≈ 11%, Mother Nature ≈ 10%, controls ≈ 9% , separators ≈ 7% • Averaging ≈105 HEP store hours per week since October 2006 • Includes few weeks of downtime to repair failed Tevatron components • Weeks of 130 store hours not uncommon • Reliability • Replaced all ≈1200 LHe Kautzky valves (cause of 2 FY06 dipole failures) • Modifying quench protection system to allow faster beam aborts • Cog pbars out of abort gap for acceleration – prevent needless quenches R. Moore - FNAL

  14. Looking Ahead in Tevatron • Implement 2nd order chromaticity correction @ low β – in progress • Simulations show improved lifetimes during HEP • Also prerequisite to pursue possible new working point near ½ integer • See A. Valishev poster (FRPMS015) • Pursue other minor improvements (few % each) – they all add up! • Scrape (higher intensity) protons @ 150 GeV • Can reduce losses up ramp and through squeeze? Need to resume • Investigating new cogging between antiproton injections • Reduce beam-beam effects by changing locations of long-range crossings • Use TELs (electron lenses) on protons for beam-beam compensation • Raise tunes of individual bunches away from resonance to improve lifetime • Better helices, improved transfer line matching, faster shot-setups, etc. R. Moore - FNAL

  15. Luminosity Projections with Updated Model Scenarios Peak Pbar Stacking Rate in Accumulator Goal = 8 fb-1 updated model scenarios 1 to 4 Only ≈1 fb-1 spread in total We’re in this area now 3 fb-1 ≈23 mA/hr June ‘07 R. Moore - FNAL

  16. Summary • Tevatron luminosity made great progress over past year • Doubled the delivered luminosity to > 3 fb-1 • Higher antiproton intensities with smaller emittances • Improved luminosity lifetime from increased separation • Tevatron upgrades complete, still reaping benefits • Continue pursuing smaller operational improvements • On track for 6-7 fb-1 total through October 2009 • 8 fb-1 is still the goal • Need increased antiproton stacking rates for higher luminosity • Make the most of the Tevatron before the end of Run 2! R. Moore - FNAL

  17. FY07 Tevatron Performance A18 vacuum leak E4 cryo vacuum D32-5 failure feeder 46B fault Oct 1 → June 24 R. Moore - FNAL

  18. 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 Magnet Motion / Orbit Stabilization R. Moore - FNAL

  19. R. Moore - FNAL

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