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PEP-II Plans and Parameters 2004-2009

PEP-II Plans and Parameters 2004-2009. John T. Seeman SLAC PEP-II MAC Meeting April 15, 2004. Topics. PEP-II status (brief) PEP-II “near” future plans (next 5 years) Conclusions. The PEP-II e + e - asymmetric collider. PEP-II Interaction Region. Luminosity signal.

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PEP-II Plans and Parameters 2004-2009

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  1. PEP-II Plans and Parameters 2004-2009 John T. Seeman SLAC PEP-II MAC Meeting April 15, 2004

  2. Topics • PEP-II status (brief) • PEP-II “near” future plans (next 5 years) • Conclusions

  3. The PEP-II e+e- asymmetric collider

  4. PEP-II Interaction Region Luminosity signal e+e--> e+e-g g

  5. 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

  6. PEP-II Betatron Tune Locations LER HER New tunes New tunes Old tunes Old tunes

  7. 50 Gauss solenoid section

  8. Solenoid fields have reduced the ECI effect November 2003: by-2 pattern (4 ns) with short mini-trains show little ECI. Fall 2003: by-3 bunch pattern (6 ns) shows very little ECI.

  9. Fall –Winter 2003-2004 Improvements • Number of bunches: • June 2003: 1030 bunches in the by-3 pattern. • April 2004: 1555 bunches in the by-2 pattern. • Parasitic collision effects are evident (~5%) • ECI effects are small (<2%) • HER and LER RF stations added to beam. • I- to 1380 mA peak. • I+ to 2380 mA peak. • Trickle charging (Continuous injection) • LER trickle injection in December • HER trickle injection in March. • by* • LER by* lowered to 11 mm last year. • HER by* lowered from 12 to 11 mm in January.

  10. Actual Run goal

  11. PEP-II operates in a beam-beam limited regime Luminosity vs I+I- Specific Luminosity vs I+I- I+I- I+I- Beam-beam parameter limit Background/lifetime limit

  12. Beam aborts average about 7 (+/- 4) per day • 4 are RF related • 41% High power RF • 25% Low level RF • 14 % Longitudinal instability • 11% RF setup • 3% Transverse instability • 2 are BaBar radiation related • 50% SVT radiation • 25% Trapped dust in HER (manual abort) • 25% Injection backgrounds • 1 is from other sources • Power supplies • Vacuum temperature monitors • Personnel Protection System • Tune management

  13. Summer 2004 PEP-II Shut-Down Activities (August 1 to October 18) • Install LER-4 RF station • Install HER-9 RF station • Install IR shield wall • Install 250 HER bellows fans • New LER synchrotron light beam size monitor • Install x-y BPM modules for two PEP-II micros • IR pump screen upgrade (?) • Injection kicker pulser upgrade • IR quadrupole power supply upgrade • New RF low-mode woofer link upgrade • New support tube chiller • New longitudinal feedback kickers in LER

  14. New transverse kicker electrodes

  15. New Longitudinal Feedback Kicker Assembly

  16. New IR2 Shield Wall for BaBar IFR

  17. LER IR2 Chamber with HOM Screen LER HOM screens need an upgrade HER robust HOM screen

  18. Overall Parameters and Goals Five times design!

  19. Luminosity Equation • To raise luminosity: lower by*, raise Ib, n, & xy.

  20. PEP-II Beam Parameters Goals • April 2004: 2.3A x 1.4 A by*=11 mm 1555 bunches L=8.4E33 • July 2004: 2.5A x 1.6 A by*=10 mm 1600 bunches L=10E33 • June 2005: 3.3A x 1.8 A by*=9 mm 1700 bunches L=15E33 • July 2006: 3.9A x 2.0 A by*=8 mm 1715 bunches L=20E33 • July 2007: 4.5A x 2.2 A by*=8 mm 1715 bunches L=24E33 • With good integration reliability and trickle injection: • 100 fb-1 more integrated by Summer 2004. • 500 fb-1 total integrated by Fall 2006. • About 1.0 to 1.3 ab-1 integrated by Fall 2009.

  21. Future Luminosity increase factors

  22. PEP-II Future Luminosity Parameters

  23. PEP-II Bunch Length Factors

  24. Supporting documentation • In the packet there are the following documents: • 1) Full luminosity parameters for each year through 2007 when the luminosity reaches it maximum. • 2) Bunch length calculations and specifications for each parameter set. • 3) Integrated luminosity plan through summer 2009.

  25. Summer-Fall 2005 PEP-II Shut-Down Activities • Install LER-5 RF station. • Install HER-10 RF station. • Remove support tube for SVT work. • Increase beam separation with stronger B1 permanent magnet. • Upgrade several high-power IR vacuum chambers (Be bellows, Q4, Q5, high power dump, Q2 bellows, LER abort window, radial ion pump, luminosity chamber, …). • HER lattice upgrade for low momentum compaction. • LER quadrupole power supply upgrades for lower by. • New RF comb filters.

  26. Modified head-on design to improve separation Stronger bends Sullivan

  27. Over all PEP-II Down Schedule 2004-2010 • 2004 down: August 1 to October 15 for BaBar IFR. • 2005 down: July 1 to December 31 for BaBar IFR and PEP-II support tube. • 2006 down: August-September. • 2007 down: August-September. • 2008 down: August-September. • 2009 down: August-September.

  28. Conclusions • PEP-II has reached a luminosity of 8.34 x 1033. • Both LER and HER are in trickle injection all the time. • PEP-II has integrated 668/pb in one day. • Total luminosity delivered over 200 fb-1. • (BaBar ~190 fb-1) • Near term upgrades are going well. • Progress for upgrades towards 2.4 x 1034 are on track. • Need specifications for a few items: • Several IR vacuum chambers • HER lattice upgrade path • B1 magnet upgrade path

  29. LER Magnets and Aluminum Vacuum System: 3 A at 3.5 GeV Magnets made by our Chinese IHEP collaborators Antechambers Reduce Electron- Cloud-Instability High power photon stops LER SR power = 2 MW.

  30. PEP-II Copper Vacuum System: 3 A at 9 GeV 4.8 A at 8 GeV Cu chambers absorbing 100 W/cm of synchrotron radiation Total SR power = 5 MW in the HER

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