Abstracts Brochure - CERN

WEPCH — Poster Session 28-Jun-06 16:00 - 18:00
applied to identify calibration errors of beam position monitors (BPMs) and quadrupoles. The linear optics was
modelled with a MATLAB based Accelerator Toolbox AT which has been developed at SLAC for the design and
commissiong of SPEAR3. For the modelling of the transverse particle motion in the TESLA-type cavities of the linear
accelerator modules, a generalized matrix solution has been included in the Accelerator Toolbox. Results of orbit
response matrix and beam matching measurements are presented and compared to simulations.
Measurement and Correction of Dispersion in the VUV-FEL
Increase in transverse beam size in the undulator
caused by dispersive effects is one of E. Prat, V. Balandin, W. Decking, N. Golubeva, T. Limberg (DESY)
the major limitations for the operation of the
VUV-FEL at DESY. Sources of the (spurious) dispersion are field errors and stray magnet fields in the undulator
beam line as well as spurious dispersion created upstream of the undulator by, for instance, rf coupler kicks, magnet
misalignments and field errors. The impact of these errors on dispersion generation depends on the actual operating
conditions of the accelerator, so the dispersion must be measured and controlled frequently. In this paper we present
a dispersion measurement procedure and first dispersion measurement and correction results obtained at VUV-FEL.
Numerical studies of the sensitivity of the spurious dispersion on various machine imperfections are presented.
Spurious Vertical Dispersion Correction for PETRA III
Spurious vertical dispersion, arising due to
the misalignment and rotational errors of G.K. Sahoo, K. Balewski, W. Decking (DESY)
magnets in synchrotron radiation sources
with low emittances, are highly undesirable as this contributes to the vertical beam size of the photon beam. This
is a matter of concern in PETRA III, a 6GeV light source with a designed horizontal emittance of 1nm.rad and 1%
emittance coupling. It has a hybrid lattice of FODO and DBA cells, which will be installed in one-eighth of the
existing PETRA II ring. In this paper local and global vertical dispersion corrections are discussed. The global vertical
dispersion is corrected using vertical corrector magnets (may also consider 12 skew quadrupole magnets), and the
skew quadrupoles are used for local correction as well. Eight of them are placed close to the two damping wiggler
sections used for minimizing the horizontal emittance. The remaining four are placed in the new octant with DBA
cells where insertion devices are installed.
Front-to-end Simulation of the Injector Linac for the Heidelberg Ion Beam Therapy Centre
The injector linac of the Heidelberg ion beam
therapy centre is currently in the commis- R. Cee (HIT) C.M. Kleffner, M.T. Maier, B. Schlitt (GSI)
sioning phase. Its main components are two
electron cyclotron resonance ion sources (ECRIS), a radio-frequency quadrupole accelerator (RFQ) and an interdigital
H-type drift tube linac (IH-DTL). It will be able to accelerate beams of hydrogen- helium- carbon- and oxygen-ions up
to a specific energy of 7 MeV per nucleon. This contribution focuses on the beam dynamics simulation of the transport
lines and the accelerating structures. Three dedicated tools have been employed: Mirko for the beam transport,
RFQmed for the particle dynamics through the RFQ and LORASR for the acceleration in the IH-DTL. Between the
different beam dynamics codes interfaces have been implemented and a front-to-end simulation has been performed.
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