Abstracts Brochure - CERN

THPCH060
THPCH061
THPCH062
THPCH064
29-Jun-06 16:00 - 18:00 THPCH — Poster Session
yields the driving transverse impedance only. Finally, simulations with Ansoft HFSS, a finite-element electromagnetic
simulator, have also been performed to crosscheck the measurement results, and study the effect of the finite kicker
length.
Simulation Study of the Dependence of the TMCI Threshold on Energy in the CERN-SPS
This paper concentrates on theoretical stud-
G. Rumolo, E. Métral, E.N. Shaposhnikova (CERN)
ies of Transverse Mode Coupling Instability
at the SPS. It shows the expected thresholds
based on a HEADTAIL tracking model and on impedance values estimated from previous measurements. First, the
effect of space charge is addressed as an important ingredient at the low energies. Subsequently, the change of TMCI
threshold possibly induced by a higher injection energy into the SPS (plausible according to the upgrade studies) is
investigated and a scaling law with energy is derived.
Tune Shift Induced by Nonlinear Resistive Wall Wake Field of Flat Collimator
F. Zimmermann, G. Arduini, R.W. Assmann, H. Burkhardt, F.
Caspers, M. Gasior, O.R. Jones, T. Kroyer, E. Métral, S. Redaelli,
G. Robert-Demolaize, F. Roncarolo, G. Rumolo, R.J. Steinhagen, J.
Wenninger (CERN)
404
We present formulae for the coherent and incoherent
tune shifts due to the nonlinear resistive
wall wake field for a single beam traveling
between two parallel plates. In particular,
we demonstrate that the nonlinear terms
of the resistive wall wake field become im-
portant if the gap between the plates is comparable to the transverse rms beam size. We also compare the theoretically
predicted tune shift as a function of gap size with measurements for an LHC prototype graphite collimator in the
CERN SPS and with simulations.
Collective Effects in the Storage Ring of Taiwan Photon Source
A new 3- 3.3 GeV synchrotron light source
P.J. Chou, C.-C. Kuo, M.-H. Wang (NSRRC)
is proposed and named the Taiwan Photon
Source (TPS). The TPS design has a natural
horizontal emittance less than 2 nm-rad and low emittance coupling, which results in small beam size. The nominal
bunch length in TPS storage ring is much shorter compared to the existing Taiwan Light Source, that makes the issue
of parasitic heating more significant. Several small-gap insertion devices are planned to provide extremely bright
x-ray photon beam. Those design features have impacts on collective beam instabilities. A preliminary study of
collective effects in the TPS storage ring is presented.
Further Studies of One-dimensional CSR Models Including the Radiation Field
K.A. Heinemann, G. Bassi, J.A. Ellison (UNM)
We are studying coherent synchrotron radiation
(CSR) from arbitrary planar orbits as
discussed in another abstract we submitted
to EPAC06. It is important to have one-dimensional approximations. Here we report on work constructing and
validating such approximations. As part of our work two well known papers by Saldin, Schneidmiller and Yurkov