Physics and technology challenges of B B factories

Conference · Wed May 01 04:00:00 EDT 1991

OSTI ID:5550834

Zisman, M S

An e{sup +}e{sup {minus}} collider designed to serve as a B factory requires a luminosity of 3 {times} 10{sup 33} cm{sup {minus}1}s{sup {minus}1} -- a factor of 20 beyond that of the best present collider and thus presents a considerable challenge to the accelerator builder. To optimize the experiment, it is necessary that the B{bar B} system have a moving center-of-mass, which implies different energies for the two beams. This feature dictates that a two-ring configuration be used. Accelerator physics issues that arise in such a design are related to the need to tightly focus the beams to a vertical beta function on the order of 1 cm, to bring the beams from two different rings into collision and then clearly separate them again, and to mask the detector region sufficiently to permit measurements with very large beam currents passing through the interaction region. Because the luminosity is limited by the beam-beam interaction, any large improvement must come from considerably increasing both the beam current and the number of bunches in the ring. These choices place many demands on accelerator technology as well as accelerator physics. Vacuum systems must be designed to handle the thermal load from a multi-ampere beam of 8--9 GeV and to maintain an adequate running pressure in the face of a large gas load from synchrotron radiation induced photodesorption. An RF system capable of supporting the high beam currents must be developed. To reduce the growth of potentially strong multibunch instabilities, the cavity higher-order modes must be highly damped to Q {le} 70. Even with a well optimized RF system, the high beam currents typically mean that wideband multibunch feedback systems are needed to maintain beam stability.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• Sponsoring Organization: DOE; USDOE, Washington, DC (USA)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5550834
• Report Number(s): LBL-30706; CONF-910505--293; ON: DE91014232
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
430100* -- Particle Accelerators-- Design
Development
& Operation
ACCELERATORS
B MESONS
BEAM DYNAMICS
BEAM LUMINOSITY
BEAM-BEAM INTERACTIONS
BEAMS
BOSONS
COLLIDING BEAMS
CP INVARIANCE
DESIGN
ELECTRON-POSITRON INTERACTIONS
ELEMENTARY PARTICLES
FEEDBACK
HADRONS
INTERACTIONS
INVARIANCE PRINCIPLES
LEPTON-LEPTON INTERACTIONS
MESON FACTORIES
MESONS
PARTICLE INTERACTIONS
PSEUDOSCALAR MESONS
RF SYSTEMS
VACUUM SYSTEMS