341 research outputs found
High Luminosity Issues for DAPhNE Upgrade
We give an overview of presentations and discussions during the Accelerator
Working Group Session dedicated to High Luminosity Issues for a future upgrade
of the Frascati e+e- Phi-Factory DAPhNE at the Workshop "e+e- in the 1-2 GeV
range: Physics and Accelerator Prospects" held at Alghero (Italy) on 10-13
September 2003.Comment: Invited talk at the Workshop on e+e- in the 1-2 GeV range, Alghero,
Italy, September 2003 (eConf c0309101
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
Study of collective effects in the CERN FCC-ee top-up booster
The CERN FCC-ee top-up booster synchrotron will accelerate electrons and
positrons from an injection energy of 20 GeV up to an extraction energy between
45.6 GeV and 182.5 GeV depending on the operation mode. These accelerated beams
will be used for the initial filling of the high-luminosity FCC-ee collider and
for keeping the beam current constant over time using continuous top-up
injection. Due to the high-intensities of the circulating beams, collective
effects may represent a limitation in the top-up booster. In this work we
present a first evaluation of the impedance model and the effects on beam
dynamics. Methods to mitigate possible instabilities will be also discussed
Strong RF Focusing for Luminosity Increase
A luminosity of a circular collider can be increased by squeezing the bunch
length at the interaction point (IP). A natural way to decrease the bunch
length is to decrease the momentum compaction factor and/or to increase the RF
voltage. However, in such a way we cannot obtain short bunches with high
currents since wakefields prevent this due to the potential well distortion and
the microwave instability. In present paper we propose to use a strong RF
focusing (with high RF voltage and high momentum compaction factor) to obtain
very short bunches at the IP with progressive bunch elongation towards the RF
cavity. This allows placing the most important impedance generating elements
near the RF cavity where the bunch is longest thus minimizing the effect of the
wakefields.Comment: 6 page
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