172 research outputs found
Aplication of Frequency Map Analysis to Beam-Beam Effects Study in Crab Waist Collision Scheme
We applied Frequency Map Analysis (FMA) - a method that is widely used to
explore dynamics of Hamiltonian systems - to beam-beam effects study. The
method turned out to be rather informative and illustrative in the case of a
novel Crab Waist collision approach, when "crab" focusing of colliding beams
results in significant suppression of betatron coupling resonances. Application
of FMA provides visible information about all working resonances, their widths
and locations in the planes of betatron tunes and betatron amplitudes, so the
process of resonances suppression due to the beams crabbing is clearly seen.Comment: 11 pages, 10 figure
Crab Waist Collision Studies for e+e- Factories
Numerical simulations have shown that the recently proposed "crab waist"
scheme of beam-beam collisions can substantially boost the luminosity of
existing and future electron-positron colliders. In this paper we describe the
crab waist concept and discuss potential advantages that such a scheme can
provide. We also present the results of beam-beam simulations for the two
currently proposed projects based on the crab waist scheme: the DAFNE upgrade
and the Super B-factory project.Comment: Invited talk at IR07 Workshop (Interaction Regions for the LHC
Upgrade, DAFNE and SuperB), 7-9 November 2007, Frascati, Ital
Simulation of Beam-Beam Effects and Tevatron Experience
Effects of electromagnetic interactions of colliding bunches in the Tevatron
had a variety of manifestations in beam dynamics presenting vast opportunities
for development of simulation models and tools. In this paper the computer code
for simulation of weak-strong beam-beam effects in hadron colliders is
described. We report the collider operational experience relevant to beam-beam
interactions, explain major effects limiting the collider performance and
compare results of observations and measurements with simulations.Comment: 23 pages, 17 figure
Design of beam optics for the Future Circular Collider e+e- -collider rings
A beam optics scheme has been designed for the Future Circular Collider-e+e-
(FCC-ee). The main characteristics of the design are: beam energy 45 to 175
GeV, 100 km circumference with two interaction points (IPs) per ring,
horizontal crossing angle of 30 mrad at the IP and the crab-waist scheme [1]
with local chromaticity correction. The crab-waist scheme is implemented within
the local chromaticity correction system without additional sextupoles, by
reducing the strength of one of the two sextupoles for vertical chromatic
correction at each side of the IP. So-called "tapering" of the magnets is
applied, which scales all fields of the magnets according to the local beam
energy to compensate for the effect of synchrotron radiation (SR) loss along
the ring. An asymmetric layout near the interaction region reduces the critical
energy of SR photons on the incoming side of the IP to values below 100 keV,
while matching the geometry to the beam line of the FCC proton collider
(FCC-hh) [2] as closely as possible. Sufficient transverse/longitudinal dynamic
aperture (DA) has been obtained, including major dynamical effects, to assure
an adequate beam lifetime in the presence of beamstrahlung and top-up
injection. In particular, a momentum acceptance larger than +/-2% has been
obtained, which is better than the momentum acceptance of typical collider
rings by about a factor of 2. The effects of the detector solenoids including
their compensation elements are taken into account as well as synchrotron
radiation in all magnets. The optics presented in this paper is a step toward a
full conceptual design for the collider. A number of issues have been
identified for further study
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