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Title |
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| MOPLT141 |
IR Upgrade Plans for the PEP-II B-Factory
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869 |
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- M.K. Sullivan, S. Ecklund, N. Kurita, A. Ringwall, J. Seeman, U. Wienands
SLAC, Menlo Park, California
- M.E. Biagini
INFN/LNF, Frascati (Roma)
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PEP-II, the SLAC, LBNL, LLNL B-factory has achieved a peak luminosity of over 7e33, more than twice the design luminosity, and plans to obtain a luminosity of over 1·1034 in the next year. In order to push the luminosity performance of PEP-II to even higher levels an upgrade to the interaction region is being designed. In the present design, the interaction point is a head-on collision with two strong horizontal dipole magnets (B1) located between 20-70 cm from the IP that bring the beams together and separate the beams after the collision. The first parasitic crossing (PC) is at 63 cm from the IP in the present by2 bunch spacing. The B1 magnets supply all of the beam separation under the present design. Future improvements to PEP-II performance include lowering the beta y * values of both rings. This will increase the beta y value at the PCs which increases the beam-beam effect at these non-colliding crossings. Introducing a horizontal crossing angle at the IP quickly increases the beam separation at the PCs but recent beam-beam studies indicate a significant luminosity reduction occurs when a crossing angle is introduced at the IP. We will discuss these issues and describe the present interaction region upgrade design.
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| MOPLT143 |
Results and Plans of the PEP-II B-Factory
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875 |
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- J. Seeman, J. Browne, Y. Cai, S. Colocho, F.-J. Decker, M.H. Donald, S. Ecklund, R.A. Erickson, A.S. Fisher, J.D. Fox, S.A. Heifets, R.H. Iverson, A. Kulikov, A. Novokhatski, M.T.F. Pivi, M.C. Ross, P. Schuh, T.J. Smith, K. Sonnad, M. Stanek, M.K. Sullivan, P. Tenenbaum, D. Teytelman, J.L. Turner, D. Van Winkle, U. Wienands, M. Woodley, Y.T. Yan, G. Yocky
SLAC, Menlo Park, California
- M.E. Biagini
INFN/LNF, Frascati (Roma)
- J.N. Corlett, C. Steier, A. Wolski, M.S. Zisman
LBNL, Berkeley, California
- W. Kozanecki
CEA/DSM/DAPNIA, Gif-sur-Yvette
- G. Wormser
IPN, Orsay
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PEP-II is an e+e- B-Factory Collider located at SLAC operating at the Upsilon 4S resonance. PEP-II has delivered, over the past four years, an integrated luminosity to the BaBar detector of over 175 fb-1 and has reached a luminosity over 7.4x1033/cm2/s. Steady progress is being made in reaching higher luminosity. The goal over the next few years is to reach a luminosity of at least 2x1034/cm2/s. The accelerator physics issues being addressed in PEP-II to reach this goal include the electron cloud instability, beam-beam effects, parasitic beam-beam effects, trickle injection, high RF beam loading, lower beta y*, interaction region operation, and coupling control.
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| MOPLT144 |
Design for a 1036 Super-B-factory at PEP-II
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878 |
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- J. Seeman, Y. Cai, F.-J. Decker, S. Ecklund, A.S. Fisher, J.D. Fox, S.A. Heifets, A. Novokhatski, M.K. Sullivan, D. Teytelman, U. Wienands
SLAC, Menlo Park, California
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Design studies are underway to arrive at a complete parameter set for a very high luminosity e+e- Super B-Factory (SBF) in the luminosity range approaching 1036/cm2/s. The design is based on a collider in the PEP-II tunnel but with an upgraded RF system (higher frequency), magnets, vacuum system, and interaction region. The accelerator physics issues associated with this design are reviewed as well as the site and power constraints. Near term future studies will be discussed.
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| MOPLT146 |
Trickle-charge: a New Operational Mode for PEP-II
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881 |
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- J.L. Turner, S. Colocho, F.-J. Decker, S. Ecklund, A.S. Fisher, R.H. Iverson, C. O'Grady, J. Seeman, M.K. Sullivan, M. Weaver, U. Wienands
SLAC, Menlo Park, California
- W. Kozanecki
CEA/DSM/DAPNIA, Gif-sur-Yvette
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In regular top-up-and-coast operation, PEP-II average luminosity is about 70…75% of the peak luminosity due to detector ramp-down and ramp-up times plus the time it takes to top-up both beams. We recently commissioned a new operational mode where the Low Energy Ring is injected continuously without ramping down the detector. The benefits?increased luminosity lifetime and roughly half the number of top-ups per shift?were expected to give an increase in delivered luminosity of about 15% at the same peak luminosity; this was confirmed in test runs. In routine trickle operation, however, it appears that the increase in delivered luminosity is more than twice that due to an increase in availability credited to the more stable operating conditions during trickle operation. In this paper we will present our operational experience as well as some of the diagnostics we use to monitor and maintain tuning of the machine in order to control injection background and protect the detector. Test runs are planned to extend trickle-charge operation to the High Energy Ring as well.
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| TUPLT153 |
Orbit Response Matrix Analysis Applied at PEP-II
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1488 |
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- C. Steier, A. Wolski
LBNL/AFR, Berkeley, California
- S. Ecklund, J.A. Safranek, P. Tenenbaum, A. Terebilo, J.L. Turner, G. Yocky
SLAC, Menlo Park, California
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Beam-based techniques to study lattice properties have proven to be a very powerful tool to optimize the performance of storage rings. The analysis of orbit response matrices has been used very successfully to measure and correct the gradient and skew gradient distribution in many accelerators. The first applications were mostly in synchrotron light sources, but the technique is also used increasingly at colliders. It allows determination of an accurately calibrated model of the coupled machine lattice, which then can be used to calculate the corrections necessary to improve coupling, dynamic aperture and ultimately luminosity. At PEP-II, the Matlab version of LOCO has been used to analyze coupled response matrices for both the LER and the HER. The large number of elements in PEP-II and the very complicated interaction region present unique challenges to the data analysis. The orbit response matrix analysis will be presented in detail, as well as results of lattice corrections based on the calibrated machine model.
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