Abstracts Brochure - CERN

TUPLS — Poster Session 27-Jun-06 16:00 - 18:00
TUPLS — Poster Session
Enhanced Optical Cooling of Ion Beams for LHC
Enhanced optical cooling (EOC) of fully
stripped lead ions in LHC is investigated.
The method of EOC is based on the usage
of pickup and kicker undulators and optical
E.G. Bessonov (LPI) A.A. Mikhailichenko (Cornell University, Department
of Physics)
amplifier. External selectivity is arranged by a moving screen located on the image plane of the optical system, projecting
the emitted undulator radiation there (see physics/0509196). Nonlinear features of cooling and requirements
to the ring lattice, optical and laser systems are discussed. Comparison with classical optical stochastic cooling (OSC)
is represented as well.
Dust Macroparticles in HERA and DORIS
Charged dust macroparticles are considered
as sources of sudden beam lifetime break- A. Kling (DESY)
downs detected in many electron storage
rings. This phenomenon is still observed in HERA, although the distributed ion pumps, which were previously
identified as dust particle sources, have been removed. We report on the observations of trapped dust during the last
period of electron operation and present a detailed model of dust macroparticle dynamics in the HERA e-ring and in
DORIS with particular emphasis on stability and possible trapping processes.
A Perfect Electrode to Suppress Secondary Electrons inside Various Magnets
Electron cloud due to multipacting in the
positron ring of B-factories is one of the lim- L. Wang (SLAC) H. Fukuma (KEK)
itations on the machine performance. Electron
cloud in the drift region can be suppressed by solenoid. However, solenoid doesn’t work inside a magnet.
Numerical studies show that there is strong multipacting in the dipole magnet of the B-factory positron ring. Electrons
also can be trapped inside quadrupole and sextupole magnets. The electron cloud from the dipole magnet and
wiggler in the positron damping ring of the ILC is a critical limitation on the choice of damping ring circumference,
which directly results in a choice of two 6km rings as the baseline for the positron damping ring. Various electrodes
have been studied using the program CLOUDLAND. Our studies show that a wire type of electrode with a few
hundred voltages works perfectly to kill the secondary electrons inside various magnets.
How Einsteinian Tide Force Affects Beam in a Storage Ring
In this paper, we will introduce Einsteinian
tide force into a storage ring, and discuss the D. Dong (IHEP Beijing)
beam characteristic in a storage ring, we can
see that it is quite different from Newtonian tide force act on beam in a storage ring which we know very well. We
also discuss the method to measure the beam instability in storage ring caused by these two different tide forces.
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