Abstracts Brochure - CERN

MOPCH095
MOPCH096
MOPCH097
26-Jun-06 16:00 - 18:00 MOPCH — Poster Session
transverse and longitudinal shaving, are described. In particular, the choice of harmonic number and its consequences
for operation and beam reproducibility are discussed. Finally, the performance achieved for the different beams is
summarized.
Performance of Nominal and Ultimate LHC Beams in the CERN PS-booster
The requirements for nominal and ultimate
M. Benedikt, M. Chanel, K. Hanke (CERN)
LHC beams in the CERN PS-Booster were
specified in 1993 and served as input for the
definition of the "PS conversion for LHC" project. Already during the upgrade project and also after its completion
in 2000, the beam intensities to be provided from the PS Booster were increased in order to compensate for changes
on the LHC machine, the beam production scheme in the PS and for non-anticipated beam losses along the injector
chain. In order to improve the beam brightness, to be compatible with the increased requirements, extensive machine
studies have taken place on the PS-Booster. The working point was changed to reduce the influence of systematic
resonances and the injection line optics was re-matched to improve the injection efficiency. The paper summarizes
briefly the evolution of the performance requirements. The various measures undertaken to improve the LHC beam
quality are outlined and the present performance achieved in the PS-Booster is presented.
LEIR Lattice
The Low Energy Ion Ring (LEIR) is a low
C. Carli, P. Beloshitsky, M. Chanel, J. Pasternak (CERN)
energy ion cooling and accumulation ring
and serves to compress long ion pulses from
Linac 3 into high density bunches suitable for LHC ion operation. Issues of the LEIR lattice are to fulfil all constraints
with a small number of quadrupoles and compensations of perturbations due to an electron cooler and gradients seen
by the beam in the bending magnets during the ramp. Furthermore, experimental investigations via orbit reponse
measurements will be reported.
CERN Proton Synchrotron Working Point Control Using an Improved Version of the Poleface-windings
and Figure-of-eight Loop Powering
R.R. Steerenberg, J.-P. Burnet, M. Giovannozzi, O. Michels, E. Métral,
B. Vandorpe (CERN)
74
The working point of the CERN Proton Synchrotron,
which is equipped with combined
function magnets, is controlled using poleface-windings.
Each main magnet consists
of one focusing and one de-focusing half-unit on which four pole-face-winding plates are mounted containing two
separate coils each, called narrow and wide. At present they are connected in series, but can be powered independently.
In addition, a winding called the figure-of-eight loop, contours the pole faces and crosses between the two
half units, generating opposite fields in each half-unit. The four optical parameters, horizontal and vertical tune and
chromaticity, are adjusted by acting on the pole-face-winding currents in both half units and in the figure-of-eight
loop, leaving one physical quantity free. The power supply consolidation project opened the opportunity to use five
independent power supplies, to adjust the four parameters plus an additional degree of freedom. This paper presents
the results of the measurements that have been made in the five-current mode together with the influence of the
magnetic nonlinearities, due to the unbalance in the narrow and wide winding currents, on the beam dynamics.