Abstracts Brochure - CERN

TUPCH — Poster Session 27-Jun-06 16:00 - 18:00
below 5 kOhm and 200 kOhm/m respectively. Numerical simulations indicate that these impedance levels can be
further reduced by more than a factor of 3 using homogeneous circular double ridged waveguides for improved coupling
to the HOMs. In the present paper the layout of an optimised homogeneous waveguide with "in vacuum" ferrite
tiles is presented, including mechanical and thermal design considerations. Low power reflectrometry measurements
demonstrate good matching of a prototype load, and high power tests of the ferrite absorber elements indicate that
the waveguide load is well suited for the cavity HOM power levels present in state of art 3rd generation SR sources.
Status of the 70 mA, 70 MeV CH Proton-DTL for FAIR
The CH-type cavity shows promising features
in the low and medium beta range: its
high accelerator gradient and the high level
of shunt impedance together with the com-
G. Clemente, H. Podlech, U. Ratzinger, R. Tiede (IAP) L. Groening
(GSI) S. Minaev (ITEP)
pact transverse dimensions make this new cavity a good candidate for proton acceleration up to 100 MeV. That’s why
GSI has decided to base the new high current proton injector for the new FAIR facility on that structure: the operating
frequency will be 352 MHz with an injection energy of 3 MeV. In order to improve the technical experience on this
new kind of structure, IAP has built a model consisting of 8 equidistant gaps for a total cavity-length of 60 cm. Several
design options with respect to welding, alignement, cooling and RF joints were studied and compared each other.
A new concept for the end-cells geometry will result in the desired flatness of the electric field along the cavity axis
and, at the same time, allow effective integration of internal quadruple lenses. Finally, the electric quadruple content
of CH-structure gaps is listed in dependence on the geometry of the cell.
Waveguide Distribution Systems for the European XFEL
In the European X-ray FEL 32 superconducting
cavities are connected to a 10 MW multi- V.V. Katalev, S. Choroba (DESY)
beam klystron through a waveguide distribution
system. The basic waveguide system is a linear system. The XFEL tunnel has limited space for the waveguide
system and therefore some new compact high power waveguide components like a motor driven phaseshifter, an
iris tuner and an asymmetric shunt tee have been developed. Also alternative layouts of the waveguide distribution
system which may have certain advantages have been designed. In this report we will present the different layouts
and report on the status of the development of the different new waveguide components.
Experience with the 208MHz and 52MHz RF Systems for the HERA Proton Accelerator
The RF System for the Hera Proton Ring
consists of four 208MHz systems and two
52MHz systems. At injection three of the
208MHz systems are at 70 kV and one System
is at 190kV with a phase of 180 degree.
R. Wagner, S. Choroba, A. Gamp, T.G. Grevsmuehl, G.M. Moeller
(DESY) A.B. Bienkowski (The Andrzej Soltan Institute for Nuclear
Studies, Centre Swierk)
The 52 MHz Systems are at 70kV each. During ramping the RF voltage of all cavities follows a ramp table. At flat
top at 920GeV both 52 MHz systems are at 50kV and three of the 208MHz Systems are at 190kV while the 180 degree
phased system is reduced to 30kV. The typical beam current is 100mA in 180 bunches with a bunch separation of 96
ns. About one year before shutdown of HERA this presentation gives an review of about 14 years operation of the
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