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PEP-II Overall Plans. John Seeman for the PEP-II Team Particle and Particle-Astrophysics Directorate Stanford Linear Accelerator Center PEP-II MAC Meeting November 15, 2007. Topics. PEP-II MAC meeting information Charge to the MAC Committee MAC agenda and talks:

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PEP-II Overall Plans

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PEP-II Overall Plans

John Seeman for the PEP-II Team

Particle and Particle-Astrophysics Directorate

Stanford Linear Accelerator Center

PEP-II MAC Meeting

November 15, 2007


  • PEP-II MAC meeting information

  • Charge to the MAC Committee

  • MAC agenda and talks:

  • Highlights of Run 6.

  • Main activities for Fall 2007 down

  • Plan for Run 7 in FY2008

  • Shut down planning

PEP-II MAC Information

  • In an emergency:

    • Fire: Leave the building by the nearest safe exit

    • Earthquake: Duck, cover, then leave the building

    • Others: Best to leave the building; meet outside

  • Meeting Rooms:

    • Thursday am: Kavli Auditorium (Kavli)

    • All the rest: Redwood Room (ROB)

  • Dinner Thursday evening (7 pm)

    • Logan Davis or Regina Matter will have maps.


  • The combined team of PEP-II and BaBar has amassed a large data set in the past nine years, reaching a total of 500 fb-1. To keep the experiment viable, this team needs to reach a total of about 750 fb-1 in the next 10 months (50% more). This requires increasing the performance in a commensurate way.

  • With regard to the PEP-II facility, the Laboratory is requesting the Machine Advisory Committee (MAC) to:

    • a) Critique the plans for maximizing the integrated luminosity in Run 7 which goes from December 2007 through September 2008.

    • b) Appraise the luminosity improvement plans to reach the peak luminosity goal in the spring of 2008.

    • c) Review the near-term focus and schedule for accelerator physics studies as they contribute to maximizing the integral for Run 7.

The PEP-II Team

Accelerator Systems Division

SLAC Support Groups


Machine Advisory Committee


The PEP-II Team

  • Run Coordinator: M. Sullivan

  • Beam dynamics: F-J. Decker, S. Heifets, A. Kulikov, U. Wienands

  • IR: S. Ecklund, W. Wittmer, M. Weaver

  • Lattice: Y. Cai, Y. Yan, G. Yocky, M. H. Wang

  • RF: A. Hill, H. Schwarz, D. Van Winkle, V. Pacak, K. Bertsche

  • HOM: A. Novokhatski, S. Weathersby, K. Ng

  • Feedback: J. Fox, A. Young, R. Akre

  • Instrumentation: A. Fisher, M. Petree, W. Cheng, M. Browne, R. Chestnut

  • Vacuum: S. DeBarger, M. Dormiani, D. Kharakh, N. Kurita, S. Metcalfe, R. Pope, N. Reeck

  • Systems: M. Zurawel, P. Smith, K. Burrows, T. Graul, T. Galetto, A. Baker

  • Operations: Operators, R. Erickson, M. Stanek, P. Schuh, W. Colocho, B. Allen

  • Much appreciated help from: Power Conversion, Software, Controls, CEF, Metrology, Klystron, Radiation Physics, Beam Physics, BaBar

Run 6 New Advances for PEP-II

  • Two new HER RF stations in, working and are ready for higher currents.

  • New skew quad fix for IR2 LER x-y coupling found and implemented. Specific luminosity is higher. More luminosity gain is expected in the future. (Decker, …)

  • Fast dither IP feedback in and working with supervision (Sullivan, Fisher, …).

  • Vertical vibration in IR support tube damped with BaBar’s help. Thanks.

Run 6 January-September 2007 Major Problems

  • Late start from the Fall 2006 down

  • Vacuum leak in HER IR Q4 chamber

  • Damaged coils on IR Quadrupole Q2

  • Bunch Injection Controller problems occurred . New system was installed.

  • VAT seal near luminosity chamber leaked.

  • HER flex-flange seals show discharges

  • More PG&E AC power dips than normal.

HER arc 5 RF seal at 6122

August 2007 was our Best month

New month and 30 day records

PEP-II Parameter Goals have not changed!

4 times design

7 times design

Fall 2007 Down Activities (September 4-December 3)

  • Finish LER BPM replacement. (Done)

  • Add 5 HER Arc HOM bellows. (To start soon)

  • Add 12 LER IR2 HOM bellows. (To start soon)

  • Replace about 192 HER Arc flex-flange RF “Omega Seals”. (5/6 done)

  • Install two new LER Q5 chambers in IR2. (Done)

  • Install repaired HER Q4L chamber. (Done)

New HOM absorbers work and more are being built.





Absorbing tiles

General Overall Plan for Run 7 (Dec 2007-Sept 2008)

  • Start the linac and PEP-II in December.

  • Run through the holidays.

  • Do more machine studies (MD) early to increase luminosity at the beginning of the run.

  • Keep in any new accelerator configuration with a luminosity improvement and then keep running!

  • Find the optimum luminosity condition by early spring.

  • Run through September with best steady state conditions.

Proposed Run Plan December-March

  • In general collide for BaBar as much as possible!

  • December goals:

    • Scrub both rings while colliding.

    • Reestablish 0.8x1034 parameters.

    • Holiday running (minimal supervision)

  • January-March goals:

    • Establish 1.7x1034 parameters.

    • Establish HER 90 degree lattice.

    • LER lower vertical emittance using IR skew quads

    • Increase HER/LER RF voltages.

    • Try lowering by*s in collision.

    • Increase beam currents

Proposed April-September Plan

  • Goals: ~April 1 start a steady state run.

    • Collide for BaBar constantly.

    • Establish 1.7 to 2.0 x 1034 parameters gradually.

    • No MDs except for tuning during collisions or for very good possibilities.

Luminosity Projection

  • We make luminosity projections using:

    • Known running months

    • Past running efficiencies (~55% with many MDs and ~68% with a few MDs)

    • Expected gains in peak luminosity (1.22.0x 1034)

    • Known downtimes

Sept 5, 2007

PEP-II projected luminosity spreadsheet


PEP-II Shut Down

  • PEP-II will stop producing data for BaBar on September 30, 2008, about ten months from now.

  • PEP-II and BaBar will then transition rapidly into a “Minimal Maintenance State (MMS)” which takes just over a year.

  • In the medium time frame, PEP-II will be at this MMS with some effort going into tunnel maintenance, safety lighting, electrical safety and mechanical safety. Valuable items will be preserved.

  • For long term, D&D of PEP-II is being studied. A DOE review held in early August 6-7, 2007.


PEP-II accelerator in Run 6 was more difficult than planned but the run ended well.

The luminosity will be ramped as fast as possible in Run 7.

PEP-II will integrate as much luminosity as possible.

Execution of the Fall 2007 shut down is going well.

Upgrades towards ~21034 will soon be done with the aim of 257 fb-1 more to 757 fb-1.

PEP-II will turn off September 30, 2008.

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