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M. Sullivan for the PEP-II Team Machine Advisory Committee Review November 15-17, 2007

Run 7 Startup Plans. M. Sullivan for the PEP-II Team Machine Advisory Committee Review November 15-17, 2007. Run 7 Startup. Start up with the machine we turned off on Sept 4 60 deg lattice Scrub rings until we can deliver RF processing as we increase currents

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M. Sullivan for the PEP-II Team Machine Advisory Committee Review November 15-17, 2007

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  1. Run 7 Startup Plans M. Sullivan for the PEP-II Team Machine Advisory Committee Review November 15-17, 2007

  2. Run 7 Startup • Start up with the machine we turned off on Sept 4 • 60 deg lattice • Scrub rings until we can deliver • RF processing as we increase currents • Run through the holiday break • Deliver and scrub until we reach 1.6 A HER and 2.3 A LER and L  8x1033 • Unknowns • How does the HER behave? • What is the abort rate?

  3. Startup (2) • Once we have a machine that is close in performance to what we had last summer • Install the 90 deg lattice for the HER • Expect to try this the first full week of Jan (7-8) • Start with currents of 1 A HER and 1.7 A LER • Look for temperature problems • Gradually increase currents to 1.6 A HER and 2.5 A LER • Watch specific lumi • Watch abort rate • Can we get back to the same luminosity? • If we are making progress and are close then keep the change • If we are far from previous lumi after several days of trying and not making significant progress then back out lattice change

  4. Startup (3) • 90 deg lattice stays in (first time) • Previous beam currents achieved and perhaps even more current • Luminosity at least as good as before • Temperature issues are under control • Headroom to go up in current • Lower HER beta y* • Detector backgrounds ok? • Luminosity increase?

  5. Startup (4) • If HER 90 deg lattice taken out • Increase HER RF voltage from 16.5 MV to 17.0 mV • Temperatures ok? • Abort rate ok? • Lower HER beta y* • Detector backgrounds ok? • Luminosity increase?

  6. Startup (5) • In parallel with HER effort…. • Increase LER RF voltage to 5 MV • Temperature issues under control? • Headroom to go to higher currents? • Lower LER beta y* • Detector backgrounds ok? • Luminosity increase? • Also in parallel, emittance control... • Construct correction for LER coupling • Implement correction (MD)

  7. Startup (7) • If 90 deg lattice fails on the first attempt… • Try to implement again if we have some understanding of why it didn’t work • This step not done if heating that can’t be fixed is what removed the 90 deg lattice • We still might be able to increase the HER RF voltage to gain some bunch shortening • Work would still continue in reducing the coupling and improving the emittance • Raising RF voltages • These steps stop as soon as we hit temperature problems we can’t fix or if the RF abort rate is too high (after some amount of processing time)

  8. Things we know we need to watch • IP bellows • Upstream of the detector NEG pumps • HER • LER • HER bpms • Ceramic chambers for kicker magnets • LER • HER • IR2 vacuum valves • 2 have been removed • 2 remain • LER abort spoiler? • Should be ok now. Overheated in the by 4 bunch pattern

  9. More things we need to watch • HER flex flange RF seals? • Should be ok now. Have to watch. • LFB kickers • Cables • Filters • Circulators • TFB kickers • Cables • Filters • Plates • LER photon stops • Bellows at ends of support tube • Whatever we have not thought of…

  10. Summary • The decision making is difficult to fully describe. We will put together a sort of the rolling 2 week plan that will be modified as we find out things • We will be exploring the limits of this machine • We will need to have a nimble response when we happen to hit a particular limit • Higher beam currents and shorter bunch lengths tend to push the machine limits in the same direction • Careful monitoring is a must as we push up the performance of this machine

  11. Backup

  12. LER RF 4.5 MV HER RF 16.5 MV Delivery starts as soon as we get to about 4 x 1033 with high but acceptable backgrounds Lumi goal of 8 x1033

  13. Put in 90 deg lattice and try very hard to make it stick Raise LER RF to 5 MV Raise HER RF to 17 MV if the above did not stick Lower βy*s Lumi goal of 11 x1033 Emittance tuning

  14. Try to get in the HER 90 deg lattice again Continue to raise beam currents Raise HER RF to 17.5 MV Lower βy*s Raise LER RF to 5.5 MV? Lumi goal of 13 x1033

  15. Continue to raise beam currents Emittance tuning Raise HER RF to 18.0 MV? Lower βy*s Lumi goal of 15 x1033 Continue optics studies

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