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PEP-II Now, Long Range, and Parameter Goals for 2003-2009

PEP-II Now, Long Range, and Parameter Goals for 2003-2009. John T. Seeman For the PEP-II Team PEP-II MAC Meeting October 9, 2003. PEP-II e + e - Collider. PEP-II is a two ring e+e- asymmetric collider. Luminosity Equation. x y is the beam-beam parameter (~0.06)

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PEP-II Now, Long Range, and Parameter Goals for 2003-2009

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  1. PEP-II Now, Long Range, and Parameter Goals for 2003-2009 John T. Seeman For the PEP-II Team PEP-II MAC Meeting October 9, 2003

  2. PEP-II e+e- Collider PEP-II MAC October 9, 2003

  3. PEP-II is a two ring e+e- asymmetric collider PEP-II MAC October 9, 2003

  4. PEP-II MAC October 9, 2003

  5. Luminosity Equation • xy is the beam-beam parameter (~0.06) • Ib is the bunch current (1 ma x 2 ma) • n is the number of bunches (~1050) • by* is the IP vertical beta (~12 mm) • E is the beam energy (3.1 and 9 GeV) PEP-II MAC October 9, 2003

  6. Overall Parameters and Goals PEP-II MAC October 9, 2003

  7. PEP-II Monthly Peak Luminosity PEP-II MAC October 9, 2003

  8. PEP-II Summer 2003 Projects • New HER # 8 RF station (+200 mA). • New HER collimator (30 m upstream). • Improved low level RF feedback circuits (higher I). • More x-y BPMs in IR2 region. • LER straight section and Arc 11 solenoid upgrade. • Octupoles for tune shift with amplitude studies. • Bellows fans on all LER bellows (~240) • IR4 HOM damper PEP-II MAC October 9, 2003

  9. Raise HER and LER currents • HER has seven RF stations with six in use. One missing a klystron. We will add one more station this summer. • LER has 3 RF stations, all in use. We will add a LER station in Summer 2004. • New low level RF controls and feedback now coming on line. • Still too many trips of RF stations. Trip rate is the same as last year but the beam currents are 15% higher. • Two new klystrons and two repaired klystrons should arrive in the next six months. PEP-II MAC October 9, 2003

  10. Lower BaBar backgrounds • BaBar backgrounds are often good. • Backgrounds can be poor during injection (mostly HER) and at high currents and luminosity. • Muon IFR outer layers are often swamped. • A new HER upstream collimator will be installed this summer.  • In LER Pb shielding will be installed upstream to reduce IFR beam spray. • Injection studies are being planned to improve reliability. HER horizontal collimator PEP-II MAC October 9, 2003

  11. Reduce the Electron Cloud Instability (ECI) Low energy electrons in the vacuum chamber are attracted to the positron beam and cause “head-tail” instabilities. This is called ECI. Solenoids have been shown to strongly reduce this effect in PEP-II by keeping the electrons near the chamber walls. This summer we plan to strengthen the solenoids in the straight sections (x 3 in field) so that bunches can be placed every 2 RF buckets (every 3 now). A chamber distance of about 1 km is to be wound. ECI in the By-2 bunch pattern PEP-II MAC October 9, 2003

  12. Octupole Magnets (from CERN) PEP-II MAC October 9, 2003

  13. Future Run Plan (Highlights) • Collide 9-10 months per year to 2009. • Five month down in Summer 2005 to install BaBar IFR upgrades, upgrade silicon tracker and PEP-II IR. • Possible 4 month down in Summer 2007 to “rotate” the Silicon tracker (radiation). • Aggressive hardware upgrade to PEP-II to get to a luminosity of 2 to 3 x 1034 by FY2006-2007. • Deliver 100 fb-1 more by Summer 2004. • Record a total of 500 fb-1 by Fall 2006. PEP-II MAC October 9, 2003

  14. Overview plans to improve the PEP-II program • “Post Run Summary” in July. • Restart the PEP-II Machine Advisory Committee. • Perform a Mid-Project Evaluation with PEP-II people and outside-the-project people to refine our tasks. • Welcomed further participation of BaBar collaborators. • Develop a firm technical upgrade plan. PEP-II MAC October 9, 2003

  15. PEP-II and KEKB Possible Luminosity Gains (estimated by J. Seeman October 2003) PEP-II MAC October 9, 2003

  16. PEP-II Integrated Luminosity Goals PEP-II MAC October 9, 2003

  17. Beam Parameters • June 2003: 1.45A x 1.1 A by*=12 mm 1034 bunches L=6.6E33 • July 2004: 2.7A x 1.6 A by*=9 mm 1450 bunches L=12.1E33 • June 2005: 3.6A x 1.8 A by*=8.5 mm 1500 bunches L=18.2E33 • July 2006: 3.6A x 2.0 A by*=6.5 mm 1700 bunches L=23.0E33 • July 2007: 4.5A x 2.2 A by*=6 mm 1700 bunches L=33.E33 • With good integration reliability: • 100 fb-1 more integrated by Summer 2004. • 500 fb-1 total integrated by Fall 2006. • About 1 to 1.4 ab-1 integrated by Fall 2009. PEP-II MAC October 9, 2003

  18. RF Parameters and Bunch Lengths PEP-II MAC October 9, 2003

  19. Major Goals for Mid-Project Evaluation Focus Groups • Parameters: • Check for consistent parameter sets for future goals. • Can we get the luminosity in other ways? (Low emittance gets 1x1033.) • Check for instability thresholds with 1700 bunches. • How bad are the parasitic collisions? • Check beam-beam effect at low by* and short bunches? • How do we make low alpha lattices? • ECI in by-2 bunch pattern? • Do we need an IP crossing angle in 2006? PEP-II MAC October 9, 2003

  20. Major Goals for Focus Groups • Lattice/Model: • Fix all beta-beats • Lower by* in both rings from 12 mm to 6.5 mm. • Raise LER nx from 38.5 to 48.5 to reduce a. More sextupoles? • Raise HER nx from 24.5 to 34.5 to reduce a. More sextupoles? • Can we get low by’s without changing the IR (like KEKB)? • Would a super-conducting IR be better to low betay? PEP-II MAC October 9, 2003

  21. Group goals (Cont.) • RF system: • Install HER-8 station in 2003 • Install LER-4 station in 2004 • Install HER-9 station in 2004 • Install HER-10 station in 2005. • Total LER current = 3600 mA. • Total HER current = 2000 mA. • Reduce RF aborts from 10 per day to 0.5 per day. • Feedback systems: • Make LLRF feedbackcapable of 3.6 x 2 A. • Make LFB system capable for 3.6 x 2 A with 1700 bunches. • Make TFB system capable for 3.6 x 2 A with 1700 bunches. PEP-II MAC October 9, 2003

  22. Group goals (cont.) • Diagnostics: • Make all BPMs with x-y readout • Improve LER synchrotron light monitor. • Vacuum systems: • New Q5 chambers • New Q4 chambers • New Abort windows • New Q1 chambers • New B1 chambers • New LER bellows • New LER transition chambers • New IR radial ion pumps • New HER Luminosity chamber • : PEP-II MAC October 9, 2003

  23. Group goals (cont.) • Reliability/Uptime: • Increase peak to average luminosity from 45% to 60%. • Reduce aborts from 10 per day to 1 per day. • Reduce chronic event failures. • Reduce single event failures. • Injection: • Increase injection rate by trickling, 60 Hz, or multi-bunches per shot. • Reduce injection losses. • Reduce BaBar backgrounds from injection. PEP-II MAC October 9, 2003

  24. Group goals (cont.) • Machine/Detector Interface: • HER current increases by 2x. • LER current increases by 2.5x. • Luminosity increases by 4x. • Is the new IR design acceptable? • New IR Design: • Lower by* to 8.5 mm in 2005. • Lower by* to 6.5 mm in 2006. • Add IP crossing angle of 4 mrad in 2006? (Beam-beam says no!) • Beam stay clear issues? • Permanent magnets or Superconducting? PEP-II MAC October 9, 2003

  25. Accelerator Improvement Projects • Likely Near Term AIP Projects • PEP-II HER9 RF Station FY2004 • PEP-II RF new windows FY2004 • PEP-II New Sextupoles for Higher Tunes FY2004 • PEP-II Quad Power Supply Upgrade for Higher Tunes FY2004 • PEP-II Longitudinal Feedback Power Amp Upgrade FY2004 • PEP-II X-Y BPM Upgrade FY200-2005 • PEP-II New LER Synchrotron Light Monitor FY2004 • PEP-II IR Low Beta Quad Upgrade FY2004-2005 • PEP-II IR2 New Shield Wall for IFR FY2004 • PEP-II Support Tube Removal Hardware Upgrade FY2004 • PEP-II Faster LER Abort kicker FY2004 • PEP-II IR2 New Q1L and Q1R Chambers FY2004-2005 • PEP-II IR2 New B1L and B1R Chambers FY2004-2005 • PEP-II IR2 New Radial Ion Pumps FY2004-2005 • PEP-II IR2 New Q2L and Q2R Chambers FY2004-2005 PEP-II MAC October 9, 2003

  26. AIP Project (Cont) • PEP-II IR2 New Q4L and Q4R Chambers FY2004-2005 • PEP-II IR2 New Q5L and Q5R Chambers FY2004-2005 • PEP-II IR2 New Luminosity Chamber FY2004-2005 • PEP-II LER photon stop temperature monitoring FY2004 • PEP-II IR2 New High Power Dump FY2005 • PEP-II Upgrade of Bong Collimator FY2005 • PEP-II LER New Abort Window FY2005 • PEP-II New Transverse feedback chambers FY2005 • PEP-II New LER High Power Bellows FY2005-2006 • PEP-II New Longitudinal Feedback System FY2006 • PEP-II LLRF Upgrade FY2006 • PEP-II New Transverse Feedback System FY2006 • PEP-II LER5 RF Station FY2005-2006 • PEP-II HER10 RF Station FY2006-2007 • PEP-II Controls and Diagnostics for Better Injection FY2006-2007 • PEP-II Better LER IR vacuum for backgrounds FY2006-2007 PEP-II MAC October 9, 2003

  27. Top Eight List of Issues • Improve the longitudinal beam and RF system stability. • Reduce injection time and injection backgrounds. • Lower by* from 12 to 9 to 6 mm. • Increase beam currents and number of bunches (x1.7). • Understand and reduce parasitic collisions. • Develop low “alpha” lattices for both rings. • Reduce unscheduled outages (now about 10%) • Strengthen our support groups. PEP-II MAC October 9, 2003

  28. Conclusions • PEP-II has exceeded twice its design luminosity and three times its design integrated luminosity per day. • PEP-II must continue to show strong improvements to keep up with the competition. • A parameter set and integration plan has been developed to reach our goals. Several issues remain to be resolved. • An aggressive construction and installation plan covering three to four years has started. PEP-II MAC October 9, 2003

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