July 7, 2008SLAC Annual Program ReviewPage 1 PEP-II in Run 7 and Transition Planning John T. Seeman Assistant Director PPA/LCLS

July 7, 2008SLAC Annual Program ReviewPage 2 Talk Overview *Brief PEP-II Layout *Run 7 operations *Transition planning *PEP-II Minimum Maintenance State *Future possibilities for PEP-II tunnel and hardware

July 7, 2008SLAC Annual Program ReviewPage 3 PEP-II Mission in FY2008 *To provide e+e- collisions to the BaBar Detector to carry out B-meson and other physics *Advance the “State of the Art” for accelerator physics for high luminosity colliders *Enter a “Minimum Maintenance State” after the collider programs terminates. *Start the study for “Deactivation and Decommissioning”.

July 7, 2008SLAC Annual Program ReviewPage 4 The PEP-II Team * PEP-II was constructed by SLAC, LBNL, and LLNL with help from BINP, IHEP, BaBar collaboration. Many thanks to the US Department of Energy And Machine Advisory Committee. 1x10 34

July 7, 2008SLAC Annual Program ReviewPage 5 Brief PEP-II History *1987: Physics: asymmetrical energies helps separate B mesons. *1991: First PEP-II CDR. *1993: Second CDR (9 GeV x 3.1 GeV). *1994: Construction started. *1997: First stored HER e - beam. *1998: First stored LER e + beam. *1998: First collisions July 23, 1998, at 12:05 pm. * : Y4S data for BaBar (433 fb - 1) *2008: Y2S (30 fb -1 ), Y3S (15 fb -1 ), and small energy scan for BaBar. *2008: Turned off PEP-II April 7, 2008, at 11:22 pm * just after setting an e+ current world record (3.2 A). * : Total delivered integrated luminosity = fb -1.

July 7, 2008SLAC Annual Program ReviewPage 6 PEP-II Layout * Two rings: Circumference = 2.2 km.

July 7, 2008SLAC Annual Program ReviewPage 7 B-Factory Overall Parameters *ParameterPEP-II * (LER/HER) *Circumference (m)2200 *Beam energy (GeV)3.1/9.0 *Number of bunches1732 *Beam currents (A)3.2/2.0 *Horizontal emittance (nm)30/45 *  y * (mm)9/11 *  y 0.06/0.05 *IP beam sizes (microns) (x/y)120/4 *Luminosity (x /cm 2 /s)12.1

July 7, 2008SLAC Annual Program ReviewPage 8 The PEP-II Collider

July 7, 2008SLAC Annual Program ReviewPage 9 PEP-II Interaction Region Components near BaBar HER LER Collision point BaBar BaBar Detector

July 7, 2008SLAC Annual Program ReviewPage 10 How the beams enter and exit the PEP-II Interaction Region

July 7, 2008SLAC Annual Program ReviewPage 11 IR Permanent Magnets

July 7, 2008SLAC Annual Program ReviewPage 12 Interaction Region Support Tube Be chamber Silicon Vertex Tracker SVT

July 7, 2008SLAC Annual Program ReviewPage 13 What worked with the PEP-II Accelerator design? *All components as designed worked to get above the design luminosity parameters (magnets, RF system, vacuum system, interaction region, background mitigation, beam instabilities, bunch-by-bunch feedbacks, injection, controls) *Major changes to get to x 4 luminosity and x 7 integrated luminosity: –Electron cloud instability needed 30 gauss solenoids on LER –Added cooling on IP Be chamber bellows. –Improved masking near IR –Added 7 RF stations to handle added current. –Improved feedback kickers –Improved RF controls –Higher power vacuum expansion bellows –Continuous injection mitigation –Shorten abort gap (3% to 1%) –Improved quadrupole lattices –Improved x-y coupling control

July 7, 2008SLAC Annual Program ReviewPage 14 PEP-II RF Cavity Early design and testing at LBL. High power production cells. Fully fitted cavity units with HOM dampers.

July 7, 2008SLAC Annual Program ReviewPage 15 * B-Factory RF Klystrons (1.2 MW)

July 7, 2008SLAC Annual Program ReviewPage 16 HOM Absorbing Bellows * HOM tiles Shield fingers

July 7, 2008SLAC Annual Program ReviewPage 17 Running before Trickle (Continuous) Injection *

July 7, 2008SLAC Annual Program ReviewPage 18 Continuous Injection for PEP-II *

July 7, 2008SLAC Annual Program ReviewPage 19 Luminosity Equation for a Circular e + e - Collider  y is the beam-beam parameter (~0.06)  I b is the bunch current (1 to 3 mA)  n is the number of bunches (~1700)  y * is the IP lattice optics function (vertical beta) (10 mm)  E is the beam energy (3.1 and 9 GeV)  (9 GeV varied to change Upsilon resonances.)  Luminosity (10 33 cm -2 s -1 )

July 7, 2008SLAC Annual Program ReviewPage 20 Beam-beam parameters * By 4 Extended  y * = ~  m.  y =  x = By 2 I - increases LER y size. I + increases LER x size. I + increases HER y size.

July 7, 2008SLAC Annual Program ReviewPage 21 PEP-II Parameters for 3.1 GeV x 9.0 GeV ParameterUnitsDesign April 2008 Best Factor over Design I+mA X 1.50 I-mA X 2.76 Number bunches X 1.04 y*y* mm /2.0 Bunch length mm /1.42 yy X 2.0 Luminosity X /cm 2 /s 312 X 4.0 Int lumi / day pb X 7.0

July 7, 2008SLAC Annual Program ReviewPage 22 Upsilon Resonances * To change center-of-mass energy, PEP-II changed HER energy (8.0 to 10.1 GeV) but not LER due to permanent magnet focusing in the interaction region. ResonanceDataHER Energy Y2S14.5 fb GeV Y3S30 fb GeV Y4S 433 fb GeV Scan above Y4S (5 MeV steps) 4.6 fb to 10.1 GeV

July 7, 2008SLAC Annual Program ReviewPage 23 PEP-II Peak Luminosity by Month ( ) * Design

July 7, 2008SLAC Annual Program ReviewPage 24 Design of 135 pb -1

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July 7, 2008SLAC Annual Program ReviewPage 26 PEP-II total integrated luminosity: 557 fb -1

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July 7, 2008SLAC Annual Program ReviewPage 28 PEP-II Uptime and Luminosity Integration vs Milestones * Uptime DOE Milestone Uptime PEP-II Actual Uptime Ratio PEP/DOE Integr. Lumin. DOE Milestone Integr. Lumin. PEP-II Actual Int. Lum. Ratio PEP/DOE FY200280% fb fb FY200380% fb fb FY200480% fb fb FY200580%42.7% fb fb FY200680%82.4% fb fb FY200780%81.1% fb fb FY200880%85.4% fb fb

July 7, 2008SLAC Annual Program ReviewPage 29 PEP-II General Accelerator “Achievements” *Introduced beta-beats to help chromatic corrections near IR. *First collider to continuously inject into a ring with the physics detector taking data. *Installed 2 km of solenoids on the e + LER ring to suppress the Electron Cloud Instability ECI. *Held the overall luminosity record for several years. Now second to KEKB (1.2 vs 1.7 x ) *Highest stored electron current (2.1 Amps) *Highest stored positron current (3.2 Amps)

July 7, 2008SLAC Annual Program ReviewPage 30 Transition planning *PEP-II Run 7 ended April 7, *PEP-II has since been kept under PPS (safety) control. *Only a very few parts have been removed for other programs. *Power usage has been minimized. *Venting, coil drying, and component removal will proceed as approval, funding, and manpower is available. *Staff: –Operators have all moved to LCLS operation. –Engineering staff moved to PEP-II minimum maintenance state, LCLS upgrades and maintenance, FACET, and PEP-X. –Physicists have moved to LCLS operations, PEP-II minimum maintenance state, FACET, PEP-X, and Super-B. –Operational PEP-II staff level (before April 7) : ~250 FTEs –Present PEP-II staff level (after April 7): ~5 FTEs. *Power: –Operational power = ~ 42 MW –MMS power = ~1.8 MW

July 7, 2008SLAC Annual Program ReviewPage 31 Budgets for PEP-II MMS and DND planning

July 7, 2008SLAC Annual Program ReviewPage 32 Future Potential Users of PEP-II Components *LCLS: a few small parts: corrector power supplies, gate valves, vacuum gauges, wire scanners, … *SPEAR-3: a few small parts: Loss monitors, streak camera, Bergos position monitor electronics. *PEP-X: Tunnel, 6 RF stations, support building, e- injection line *Super-B: All magnets, all power supplies, all electronics modules, 10 RF stations, all supports, all vacuum chambers *Project X: Magnets with vacuum chambers for transport lines *LBNL ALS : Chopper power supplies for ALS bends *J-Lab: Electro-magnets for energy upgrade

July 7, 2008SLAC Annual Program ReviewPage 33 PEP-X (SLAC Today July 3)

July 7, 2008SLAC Annual Program ReviewPage 34 PEP-II : Thanks to all! *