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Super-B Accelerator R&D

Super-B Accelerator R&D

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Super-B Accelerator R&D

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  1. Super-B Accelerator R&D J. Seeman With contributions from the Super-B Staff September 17, 2009

  2. Outline • Overview • Super-B parameters • Frascati DAFNE crab waist results • Interaction region • Lattice • Polarization • PEP-II reusable components • Conclusions

  3. Super Factories Linear colliders Factories B-Factories F-Factories Future Colliders e+e- Colliders

  4. Super-B Project • Super-B aims at the construction of a very high luminosity (1x 1036 cm-2 s−1) asymmetric e+e− flavor factory with a possible location on or near the campuses of the University of Rome at Tor Vergata or the INFN Frascati National Lab. • Aims: • Very high luminosity (~1036) • Flexible parameter choices. • High reliability. • Longitudinally polarized beam (e-) at the IP (>80%). • Ability to collide at the Charm threshold.

  5. Super-B Accelerator Contributors (~Fall 2009) • D. Alesini, M. E. Biagini, R. Boni, M. Boscolo, A. Clozza, T. Demma, A. Drago, M. Esposito, A. Gallo, S. Guiducci, V. Lollo, G. Mazzitelli, C. Milardi, L. Pellegrino, M. Preger, P. Raimondi, R. Ricci, C. Sanelli, G. Sensolini, M. Serio, F. Sgamma, A. Stecchi, A. Stella, S. Tomassini, C. Vaccarezza, M. Zobov (INFN/LNF, Italy) • K. Bertsche, A. Brachmann, Y. Cai, A. Chao, A. DeLira, M. Donald, A. Fisher, D. Kharakh, A. Krasnykh, N. Li, D. MacFarlane, Y. Nosochkov, A. Novokhatski, M. Pivi, J. Seeman, M. Sullivan, U. Wienands, J. Weisend, W. Wittmer, G. Yocky (SLAC, US) • A. Bogomiagkov, S.Karnaev, I. Koop, E. Levichev, S. Nikitin, I. Nikolaev, I. Okunev, P. Piminov, S. Siniatkin, D. Shatilov, V. Smaluk, P. Vobly (BINP, Russia) • G. Bassi, A. Wolski (Cockroft Institute, UK) • S. Bettoni (CERN, Switzerland) • M. Baylac, J. Bonis, R. Chehab, J. DeConto, Gpmez, A. Jaremie, G. Lemeur, B. Mercier, F. Poirier, C. Prevost, C. Rimbault, Tourres, F. Touze, A. Variola (CNRS, France) • A. Chance, O. Napoly (CEA Saclay, France) • F. Bosi, E. Paoloni (Pisa University, Italy)

  6. A New Idea • Pantaleo Raimondi came up with a new scheme to attain high luminosity in a storage ring • Change the collision so that only a small fraction of one bunch collides with the other bunch • Large crossing angle • Long bunch length • Due to the large crossing angle the effective bunch length (the colliding part) is now very short so we can lower y* by a factor of 50 • The beams must have very low emittance – like present day light sources • The x size at the IP now sets the effective bunch length • In addition, by crabbing the magnetic waist of the colliding beams we greatly reduce the tune plane resonances enabling greater tune shifts and better tune plane flexibility • This increases the luminosity performance by another factor of 2-3

  7. xy Vertical beam-beam parameter Ib Bunch current (A) n Number of bunches by* IP vertical beta (cm) E Beam energy (GeV) Present day B-factories PEP-II KEKB E(GeV) 9x3.1 8x3.5 Ib 1x1.6 0.75x1 n 1700 1600 I (A) 1.7x2.7 1.2x1.6 y* (cm) 1.1 0.6 y 0.08 0.11 L (x1034) 1.2 2.0 How to get 100 times more Luminosity equation Answer: Increase Ib Decrease y* Increase y Increase n

  8. Crab Waist Scheme (Raimondi)

  9. Beam distributions at the IP Without Crab-sextupoles Crab sextupoles OFF waist line is orthogonal to the axis of one bunch Crab sextupoles ON With Crab-sextupoles waist moves to the axis of other beam E. Paoloni All particles from both beams collide in the minimum by region, with a net luminosity gain

  10. Crossing Angle Test at DAFNE

  11. Data averaged for a full day by=9mm, Pw_angle=1.9 Luminosity [1028 cm-2 s-1] by=25mm, Pw_angle=0.3

  12. Super-B Parameter Options

  13. SuperB Site Choices C ~1.4 km Frascati National Laboratories Existing Infrastructure

  14. Roman Villa Collider Hall SuperB LINAC SPARX SuperB footprint at Tor Vergata Storage rings length = 1800 m

  15. Perspective view

  16. Layout: PEP-II magnets reuse Dipoles Available Needed Quads Sexts All PEP-II magnets can be used, dimensions and fields are in range RF requirements are met by the present PEP-II RF system

  17. PEP-II Magnets and RF Components

  18. Arc Lattice Raimondi, Biagini, Wittmer, Wienands • Arc cell: flexible solution is based on decreasing the natural emittance by increasing mx/cell, and simultaneously adding weak dipoles in the cell drift spaces to decrease synchrotron radiation • All cells have: mx=0.75, my=0.25  about 30% fewer sextupoles • Better DA since all sextupoles are at –I in both planes (although x and y sextupoles are nested) • Distances between magnets compatible with PEP-II hardware • All quads-bends-sextupoles in PEP-II range Arcs & FF

  19. W. Wittmer

  20. Lattice Layout (Two Rings) (Sept 2009) Y. Nosochkov

  21. x-y resonance suppression D.Shatilov’s (BINP), ICFA08 Workshop Much higher luminosity! Crab Waist On: 1. large Piwinski angleF >> 1 2.bycomparable withsx/q Typical case (KEKB, DAFNE): 1. low Piwinski angleF< 1 2.bycomparable withsz

  22. Comparison of design and achieved beam emittances (*achieved) Emittance tuning techniques and algorithms have been tested in simulations and experiments on the ATF and on the other electron storage rings to achieve such small emittances (ex. CesrTA as an ILC-DR test facility has a well established one).

  23. Polarization versus Energy of HER (Wienands)

  24. RF Plan: Use PEP-II RF system and cavities (Novokhatski, Bertsche)

  25. PEP-II RF Cavities match Super-B needs.

  26. Super-B RF Parameters (Sept 2009)

  27. Injector Layout 1) dipole α and g…. on-off @ 50 Hz 2) dipole βandq…. DC dipoles 4) dipoles l and d ….. Pulsed inverted dipoles @ 50 Hz e- DR R A C D B θ α g β L - 0.8 GeV GUN SHB 5.7 GeV 0.8 GeV 0.1GeV > 7 GeV e+ ≈ 60 m. ≈ 70 m. PS ≈ 320 m. e+ DR ≈ 400 m. R. Boni

  28. The IR design • The interaction region design has to accommodate the machine needs as well as the detector requirements • Final focus elements as close to the IP as possible • As small a detector beam pipe as backgrounds allow • As thin as possible detector beam pipe • Adequate beam-stay-clear for the machine • Low emittance beams helps here • Synchrotron radiation backgrounds under control • Adequate solid angle acceptance for the detector

  29. Final focus magnets • Up to now, factories have typically developed interaction regions with at least one shared quadrupole • However, with the large crossing angle of the SuperB design this means at least one beam is far off axis in a shared magnet • This magnet therefore strongly bends the off-axis beam which produces powerful SR fans and even emittance growth • To avoid this, the SuperB design has developed a twin final focus doublet for both beams

  30. Coils array Total field in black R&D on SC Quadrupoles at the IP Most recent design with BSC envelopes E. Paoloni (Pisa), S. Bettoni (CERN)

  31. SC Quadrupoles at the IP (E. Paoloni, S. Bettoni)

  32. Inside the detector M. Sullivan

  33. Photons/beam bunch M. Sullivan HER 2.5e6 LER 2.9e7 6.9e5 9.9e6 15680 5.7e5

  34. TDR Topic List • Vacuum system • Arcs pipe • Straights pipe • IR pipe • e-cloud remediation electrodes • bellows • impedance budget simulations • pumping system • Diagnostics • Beam position monitors • Luminosity monitor • Current monitors • Synchrotron light monitor • R&D on diagnostics for low emittance • Feedbacks • Transverse • Longitudinal • Orbit • Luminosity • Electronics & software • Control system • Architecture • Design • Peripherals • Injection System • Polarized gun • damping rings • spin manipulators • linac • positron converter • beam transfer systems • Collider design • Two rings lattice • Polarization insertion • IR design • beam stay clear • ultra-low emittance tuning • detector solenoid compensation • coupling correction • orbit correction • stability • beam-beam simulations • beam dynamics and instabilities • single beam effects • operation issues • injection scheme • RF System • RF specifications • RF feedbacks • Low level RF • Synchronization and timing • Site • Civil construction • Infrastructures & buildings • Power plants • Fluids plants • Radiation safety • Magnets • Design of missing magnets • Refurbishing existing magnets • Field measurements • QD0 construction • Power supplies • Injection kickers • Mechanical layout and alignment • Injector • supports

  35. Conclusions • Crossing angle collisions work well experimentally at DAFNE. • Parameters for a high luminosity collider seem to hold together. Both Super-B and Super-KEKB now have similar parameters. • Detailed site work and lattice layout computations are advancing. • IR design is coming together • Working on accelerator tolerances now. • Aiming at a White Paper at end of 2009 and TDR at end of 2010.