Abstracts Brochure - CERN

MOPLS — Poster Session 26-Jun-06 16:00 - 18:00
Efficient Collimation and Machine Protection for the Compact Linear Collider
We present a new approach to machine protection
and collimation in CLIC, separating R.W. Assmann, F. Zimmermann (CERN)
these two functions: If emergency dumps in
the linac protect the downstream beam line against drive-beam failures, the energy collimation only needs to clean
the beam tails and can be compact. Overall, the length of the beam delivery system is significantly reduced.
Commissioning Status of the CTF3 Delay Loop
The CLIC Test Facility CTF3, built at CERN
by an international collaboration, aims at
demonstrating the feasibility of the CLIC
scheme by 2010. In particular, one of the
main goals is to study the generation of high-
R. Corsini, S. Doebert, F. Tecker, P. Urschütz (CERN) D. Alesini, C.
Biscari, B. Buonomo, A. Ghigo, F. Marcellini, B. Preger, M. Serio, A.
Stella (INFN/LNF)
current electron pulses by interleaving bunch trains in delay lines and rings using transverse RF deflectors. This will
be done in the 42 m long delay loop, built under the responsibility of INFN/LNF, and in the 84 m long combiner ring
that will be installed in 2006. The delay loop installation was completed, and its commissioning started at the end of
2005. In this paper the commissioning results are presented, including the first tests of RF injection.
Luminosity Tuning at the Interaction Point
Minimisation of the emittance in a linear collider
is not enough to achieve optimal perfor- P. Eliasson, M. Korostelev, D. Schulte, F. Zimmermann (CERN)
mance. For optimisation of the luminosity,
tuning of collision parameters such as angle, offset, waste, etc. is needed, and a fast and reliable tuning signal is
required. In this paper tuning knobs are presented, and their optimisation using bemstrahlung as a tuning signal is
studied.
Investigations of DC Breakdown Fields
The need for high accelerating gradients for
the future 30 GHz multi-TeV e T. Ramsvik, S. Calatroni, A. Reginelli, M. Taborelli (CERN)
+ e − Compact
Linear Collider (CLIC) at CERN has triggered
a comprehensive study of DC breakdown fields of metals in UHV. The experimental setup is based on a
capacitor discharge across a gap junction. The simple design and fully automated computer control enable breakdown
fields and dark current of numerous materials to be measured. The study shows that Mo, W and Ti reach
high breakdown fields, and are thus good candidates for the iris material of CLIC structures. For untreated Mo the
breakdown field is higher than Cu but the conditioning speed is slower. Ti, on the other hand, shows acceptable
conditioning speeds, but material erosion makes this solution problematic. Feasible solutions to increase the spark
conditioning speed for the case of Mo are presented together with attempts to prevent Ti erosion. For some of the
materials studied a significant reduction in the saturated breakdown field was observed upon gas exposure during
intensive spark conditioning. As an example, a 50% decrease of the breakdown field of Mo is recorded when spark
conditioning is carried out in an environment of 10 -5 mbar air.
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