Abstracts Brochure - CERN

MOPLS082
MOPLS083
MOPLS084
26-Jun-06 16:00 - 18:00 MOPLS — Poster Session
Simulation of the ILC Collimation System Using BDSIM, MARS15 and STRUCT
J. Carter, I.V. Agapov, G.A. Blair, L. Deacon (Royal Holloway, University
of London) D.A.-K. Angal-Kalinin, F. Jackson (CCLRC/DL/
ASTeC) A.I. Drozhdin, N.V. Mokhov (Fermilab) A. Seryi (SLAC)
132
The simulation codes STRUCT, MARS15 and
BDSIM are used to simulate in detail the collimation
section of the ILC. A comparative
study of the collimation system performance
is performed, and the key radiation loads are
calculated. Results for the latest ILC designs are presented together with their implications for future design iterations.
Higher Order Mode Study of Superconducting Cavity for ILC Baseline
K.W. Watanabe (GUAS/AS) H. Hayano, E. Kako, S. Noguchi, T.
Shishido (KEK)
The superconducting cavity of ILC baseline
shape is being developed at KEK-STF (Superconducting
RF Test Facility). The Higher
Order Mode (HOM) of the cavity is one study
item for the development. The purpose of the HOM study is further optimization of TTF HOM coupler and measurement
of the HOM field distribution and the polarization of the main dipole modes. The result will be applied
to HOM readings of beam induced signal for the purpose of cavity offset position and angle of axis measurement
relative to the beam. We tried to improve of TESLA-type HOM coupler for more small size and relaxation of second
stop-band. The cold-model coupler was made, and the RF characteristic was measured. After HOM couplers welded
to the KEK Baseline nine-cell SC cavity, Qext of fundamental mode and each HOM, field pattern of each HOM and
polarization of dipole modes were measured by the network analyzer. The results of the improved HOM coupler are
presented.
Experimental Comparison at KEK of High Gradient Performance of Different Single Cell
Superconducting Cavity Designs
We have performed a series of vertical tests of
F. Furuta (KEK)
three different designs of single cell Niobium
superconducting cavities at 2 degrees Kelvin.
These tests aimed at establishing that an accelerating gradient of 45 MV/m could be reached in any of the designs,
while using the standard KEK surface preparation. The designs tested were the Cornell re-entrant shape (RE), the
DESY/KEK low loss shape (LL), and the KEK ICHIRO series. The cavities underwent surface preparation consisting
of centrifugal barrel polishing, light chemical polishing, electropolishing, and finally a high pressure water rinse. All
three kinds of cavities were used in a series of vertical tests to investigate details of the surface treatment. When using
ultra-pure water for the high pressure rinse, the LL cavity reproducibly exceeded a gradient of 45 MV/m, the RE
design reproducibly reached a gradient of between 50 MV/m and 52 MV/m, and three of the six ICHIRO cavities
reached a gradient of between 45 MV/m and 49 MV/m.