Abstracts Brochure - CERN

MOPCH — Poster Session 26-Jun-06 16:00 - 18:00
an overall cryogenic power of 30 W at 4.2 K, is composed of two quarter wave type 88 MHz rf resonator providing a
minimum of 6.5 MV/m with a quality factor of 1 10 9, two tuning mechanisms controlling the resonator frequency
and an alignment system allowing to adjust the cavity position with a ± 1 mm accuracy. Several tests performed on a
first resonator prototype fabricated by the "Ettore Zanon SpA" Company, have validated the cavity and its auxiliary
components design. A first cryomodule fully equipped (cavities, cryostat, tuning and alignment systems), planned to
be tested at the beginning of 2007, is under manufacturing. The details of the cryomodule design and the resonator
tests results are discussed in the paper.
Developments in Conditioning Procedures for the TTF-III Power Couplers
The Laboratoire de l’Accélérateur Linéaire
(LAL) has the task of preparation and con- H. Jenhani, T. Garvey, M. Omeich, C.P. Prevost, V. Variola (LAL)
ditioning of thirty TTF-III couplers for the
VUV FEL superconducting linear accelerator project at DESY. These couplers will be mounted on the cryo-modules
of the VUV-FEL linac and their operation will provide valuable experience for the European XFEL project. The latter
project will use 1,000 couplers of the TTF-III type. Such couplers are also the baseline for the International Linear
Collider (ILC) which would require between 10,000 and 20,000 units. For projects which require couplers in such
large numbers, conditioning time becomes a important consideration in terms of time and cost. As the couplers
themselves are complex RF elements, for which multiple mechanical fabrication techniques are used, one may find
variations between the finished objects. This may lead to varying conditioning times from one coupler to another.
We will present the results of our conditioning experience with the TTF-III couplers and discuss variations in the
conditioning procedure aimed at reducing the processing time needed while operating in a safe and reliable fashion
in order to protect the coupler.
First RF Tests in the HoBiCaT Superconducting Test Facility at BESSY
In preparation for the construction of the
BESSY-FEL User Facility, BESSY recently
completed the installation of the HoBiCaT
cryogenic test facility for superconducting RF
(SRF) TESLA cavity units, including all an-
J. Knobloch, W. Anders, J. Borninkhof, H.G. Hoberg, S. Klauke, O.
Kugeler, M. Martin, G. Mielczarek, A. Neumann, D. Pflückhahn, S.
Rotterdam, M. Schuster, T. Westphal (BESSY GmbH)
cillary devices (helium tank, input coupler, tuner, magnetic shielding). It is designed to house two such units in a
configuration similar to that envisaged for the superconducting CW linac of the BESSY FEL. Commissioning of the
facility is now complete and the first TTF-III RF coupler and cavity unit have been tested. In particular, the complete
production, cleaning and assembly of the cavity unit was carried out by industry. These tests thus serve as a first
step at qualifying industrial partners for series production of such systems, which will be essential for the future
construction of SRF based light sources. Results will be presented.
Microphonics Measurements in a CW-driven TESLA-type Cavity
Superconducting cavities with a high quality
factor exhibit a very low bandwidth in their O. Kugeler, W. Anders, J. Knobloch, A. Neumann (BESSY GmbH)
resonant frequency, which makes their operation
very sensitive to mechanical oscillations. In CW mode of operation, as is intended for the BESSY-FEL Linac,
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