Abstracts Brochure - CERN

THPCH — Poster Session 29-Jun-06 16:00 - 18:00
measure perpendicular shifts. We will present technique, results and resolutions of our distance meter prototype.
We will also examine their applications at the ILC.
Status of the ELETTRA Global Orbit Feedback Project
A fast digital feedback system is under development
to stabilize the electron beam closed M. Lonza, D. Bulfone, R. De Monte, V. Forchi’, G. Gaio (ELETTRA)
orbit at the ELETTRA storage ring in the
band up to 300 Hz. In view of the implementation of the feedback, the existing orbit measurement system will
be upgraded to allow for better accuracy in the beam position measurement and higher acquisition rate. A global
correction algorithm running on a number of distributed processing units will correct the orbit using all of the storage
ring steerer magnets. The status of the project development is given in this article.
Single-loop Two-dimensional Transverse Feedback for Photon Factory
We installed a 500MS/s single-loop two-dimensional
transverse bunch-by-bunch feedback
system in the Photon Factory ring at
KEK and the system is in operation at its user
T. Nakamura, K. Kobayashi (JASRI/SPring-8) W.X. Cheng, T.
Honda, M. Izawa, T. Obina, M. Tadano (KEK)
mode. The system composed of a single feedback loop; one skewed pair of BPM electrodes and one kicker stripline
at skewed position to detect position and kick horizontally and vertically with a single signal line, and a SPring-8
feedback processor. Consequently, this system is easy to tune and cost effective. SPring-8 feedback processor employs
FPGA that has enough computing power for processing more than 20-tap FIR filter required for newly developed twodimensional
feedback signal processing. We report the principle of the system, the result of test and the experience.
Bunch-by-bunch Feedback for the Photon Factory Storage Ring
After the straight-section upgrade in 2005,
the PF (Photon Factory) ring will start the
top-up operation or the continuous mode in
2006. Previously the octupole magnets were
W.X. Cheng, T. Honda, M. Izawa, T. Obina, M.T. Tadano, M. Tobiyama
(KEK) K. Kobayashi, T. Nakamura (JASRI/SPring-8)
used to suppress the transverse coupled bunch instability and RF modulation method to enhance the bunch length
has been effectively used to suppress the longitudinal instabilities. However, such kind of methods are not suitable for
the top-up operation, we are preparing active bunch-by-bunch feedback systems for both transverse and longitudinal
plane. The transverse feedback system has been installed along with the straight-section upgrade, this system uses a
FPGA based feedback processor board developed at the SPring-8, both horizontal and vertical signals are processed
in a single control loop. For the longitudinal feedback, a two-port DAFNE type wide-band cavity has been designed
and is now manufacturing, a digital signal processing part is under design, the whole system will start commissioning
in autumn 2006.
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