05-04-2012, 11:18 AM
Future Very High Luminosity Options for PEP-II
WGA10.PPT (Size: 2.72 MB / Downloads: 81)
Lessons learned from the present B-Factories
Asymmetric beam energies work.
Energy transparency conditions are weak.
Interaction regions with asymmetry can be operated.
IR backgrounds can be handled.
High current RF can be operated. (1A x 2 A).
Bunch-by-bunch feedbacks work (4 nsec spacing).
Beam-beam tune shifts reached 0.08 (v) to 0.10 (h).
Injection rates good. Continuous injection feasible!
Electron Cloud Instability (ECI) ameliorated for now!
New techniques of the Next Generation B-Factory
Beam lifetimes will be low continuous injection.
Very low by* (6 to 12 mm1.5 to 3 mm).
Higher tune shift (trade beam-beam lifetimes for tune shifts).
Higher beam currents (x 10 or so) (Watch total power!).
Higher frequency RF (more bunches).
Bunch-by-bunch feedbacks at the 1 nsec scale. (StartedFox)
Very short bunch lengths (2-3 mm).
High power vacuum chambers with antechambers and improved or no bellows. (Started)
Reduce energy asymmetry to save wall power.
Advanced B Factory with New RF Frequency
Higher RF frequency provides for more bunches.
Better for resistive wall losses, Touschek lifetime, single bunch instabilities, lower beam emittance, perhaps lower parasitic beam-beam effects, less peak synchrotron radiation heat stress, …
Future BF activities
Planned workshops:
October 13-16, 2003 at SLAC: ICFA Workshop on e+e- High Luminosity Colliders.
Super-B 10^36 Particle Physics Workshop at SLAC October 22-24.
Joint KEK/SLAC Super-B-Factory workshop in January 19-22, 2004 in Oahu, Hawaii.
Conclusions
The parameters of a Super-PEP-II were studied with RF frequencies of 476 MHz.and 952 MHz.
At the present, for about 120 MW of total power, linac and campus included:
476 MHz provides a luminosity of about 5E35 and
952 MHz provides a luminosity of about 1E36 with beam-beam parameters of 0.15.
Coupled-bunch beam-dynamics effects, IR design, and vacuum systems will be studied next.