Abstracts Brochure - CERN

MOPCH150
MOPCH151
MOPCH152
26-Jun-06 16:00 - 18:00 MOPCH — Poster Session
microphonics are therefore the dominant error source for field stability. In order to compensate the detuning, it is
necessary to properly characterize amplitude and frequency with respect to all involved mechanical and electrical
components. Such measurements have been performed at the HoBiCaT test facility at BESSY and will be described
in detail.
Characterization of a Piezo-based Microphonics Compensation System at HoBiCaT
A. Neumann, W. Anders, S. Klauke, J. Knobloch, O. Kugeler, M.
Schuster (BESSY GmbH)
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In the superconducting driver linac for the
BESSY FEL, piezo actuators will be utilized
to rapidly counteract the detuning of the cavity
resonance caused by nm mechanical os-
cillations (microphonics). This is of importance to guarantee field stability and lower the power consumption of the
RF system for the superconducting cavities. To design a suitable compensator, mechanical and electro-mechanical
transfer functions, as well as the tuning range of the system under operating conditions have been measured and will
be presented.
Pulsed RF System for the ELBE Superconducting Accelerator
A. Buechner, F.G. Gabriel (FZR/FWFE) H. Buettig, U. Lehnert, P.
Michel, Ch. Schneider, R. Schurig (FZR)
The RF system for the ELBE accelerator was
originally designed for cw mode. Although
this works problem-free tests have shown
that it is possible to reach higher gradients
in the TESLA cavities with a pulsed RF system. The new RF system will be presented together with measurements of
the achievable gradients. Roughly 30% higher gradients could now be used in pulsed mode. As positive side effects
the radiation by field emission is reduced by the duty cycle and an easy in situ RF conditioning of cavities and coupler
windows is possible.
A Pulse RF High-power Processing Effect of Superconducting Niobium Cavities Observed
at the ELBE Linear Accelerator
U. Lehnert, H. Buettig, P. Michel, Ch. Schneider, R. Schurig (FZR)
A. Buechner, F.G. Gabriel (FZR/FWFE)
The driver LINAC of the ELBE radiation
source is built for cw operation. However,
in some cases a pulsed-mode operation was
desired to extend the otherwise stringent gra-
dient limits. The main restriction results from field emission that decreases the Q of the cavities which was evaluated
from measurements of the liquid helium consumption. After pulsed-mode operation with gradients exceeding the
maximum cw accelerating gradients by 30–40