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Recent FNAL Collider Operations
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  1. Recent FNAL Collider Operations Ron Moore Fermilab – Tevatron Dept.

  2. Hooray for record luminosities! How’d you do it? • Notable achievements since the long shutdown ended • Delivered lumi / week = 33.3 pb-1 • Delivered lumi from Aug 28-Sep 3 ≈ 119 pb-1 • Peak luminosity = 229 1030 cm-2 s-1(store 4964 average, before D0 correction) • Record # pbars at start HEP ≈ 2870 109 • Contents • Ingredients to record running • Tevatron: efficiencies, luminosity lifetime • Recycler: new working point  smaller emittances • Pbar Source: near record stacking rates • Proton Source: near record beam intensity • Reliability (and little luck) • FY07 Plan R. Moore - FNAL

  3. FY06 Shutdown Where have we been? FY06 Outcome Tevatron B1 Repairs/ Start-up Tevatron A4 Warm-up/ Repairs R. Moore - FNAL

  4. Run II Peak Luminosities R. Moore - FNAL

  5. Luminosity Formula • N = bunch intensity, f = collision frequency • ε = transverse emittance (size), σz = bunch length • H = “hour glass” factor (<1, accounts for beam size over finite bunch length) Increasing the Luminosity • Decrease β* (new 28 cm β* lattice in Sep 05) • Increase Na and/or decrease εa from Recycler + electron cooling • Increase Np R. Moore - FNAL

  6. Increasing Beam Intensities 10000 E9  278 E9 / bunch 2700 E9  75 E9 / bunch R. Moore - FNAL

  7. Reduced Tevatron Beam Loss @ 150 GeV R. Moore - FNAL

  8. Reduced Beam-Beam Effects @ 150 GeV • Protons suffered from higher pbar intensities • New helix (separator voltages) increased separation, especially at worst crossing point R. Moore - FNAL

  9. Tevatron Luminosity Lifetimes • Long-range beam-beam effects degrade luminosity lifetime + integral • Nearest parasitic crossings (≈59 m from IPs) especially bad • During shutdown, additional separators installed to increase separation • More separation  reduced beam-beam effects • ~20% increase @ upstream IP • Not as much @ downstream IP • Luminosity lifetime improved ~20% compared to pre-shutdown running • Increased integrated luminosity per store (for given store length) 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. Comparing HEP Stores to Model • Luminosity evolution during HEP now agrees better to model without beam-beam effects • Most pbars lost during HEP are burned in luminosity • That’s good! • Protons suffer more from beam-beam effects • Especially with smaller pbars V. Lebedev R. Moore - FNAL

  12. New Recycler Working Point • During HEP shot-setup, Recycler “momentum-mines” 9 parcels that become the 9 pbar transfers (4 bunches/transfer) shot to the Tevatron • Poor lifetime and high transverse emittance growth rate in that state • New tune working point reduced emittance growth rate (mid-August) • Brighter (smaller emittance) pbars delivered to Tevatron • Higher instantaneous luminosity for same number of pbars • (Smaller emittances also improves pbar and proton efficiencies in Tevatron) • Currently limiting max Recycler pbar “stash” to 400 1010 • Increase as experience and pbar stacking rate allow R. Moore - FNAL

  13. Pbar Stacking • Started slowly after shutdown, partly due to Booster proton output • Ramped up to record performance (20.5 mA / hr peak yesterday) • Increasing stacking still most direct route to higher Tev luminosities Average Stacking Rate [1010 mA / hr] Pbars Delivered [1010] R. Moore - FNAL

  14. Protons on Pbar Target Now > 8 1012 protons / pulse on target R. Moore - FNAL

  15. Reliability 5 store running averages Motherhood statement: You can’t integrate luminosity if you aren’t running… Mother Nature statement: How’d you like Monday’s storm? I won that round… R. Moore - FNAL

  16. Where do we go from here? The FY07 Plan ~2x existing dataset Ramp up to 48 pb-1/ week 8 week shutdown R. Moore - FNAL

  17. FY07 Plan for Peak Luminosity R. Moore - FNAL

  18. Summary • Record running thanks to performance and reliability of all machines • More protons on pbar target (Linac / Booster / Main Injector) • Near record pbar stacking rates (Debuncher / Accumulator) • Smaller pbar emittances from Recycler • More beam to HEP and improved luminosity lifetime in Tevatron • Good reliability and luck to avoid (most of) Mother Nature’s wrath • Current Tevatron Records • Delivered luminosity / week = 33.3 pb-1 • Peak luminosity = 229 1030 cm-2 s-1 • FY07 plan • Deliver ≈ 1800 pb-1 at up to 48 pb-1/ week • Reach peak luminosity 3.2 1030 cm-2 s-1 • 8 week shutdown during summer R. Moore - FNAL

  19. NuMI (120 GeV) MiniBoone (8 GeV) A1 Line P1 Line R. Moore - FNAL

  20. R. Moore - FNAL

  21. FY07 Plan for Weekly Integrated Lumi R. Moore - FNAL

  22. Run II Luminosity Projections Zero-Stack Pbar Stacking Rate Design Now on this line R. Moore - FNAL