Abstracts Brochure - CERN

WEPLS041
WEPLS042
WEPLS043
28-Jun-06 16:00 - 18:00 WEPLS — Poster Session
Enhanced Wakefield Transformer Ratio Experiment at Argonne Wakefield Accelerator
A. Kanareykin, C.-J. Jing (Euclid TechLabs, LLC) M.E. Conde, W.
Gai, R. Konecny, J.G. Power, Z.M. Yusof (ANL)
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We present preliminary data and analysis on
recent enhanced wakefield transformer ratio
experiment at Argonne Wakefield Accelerator
Facility. The method uses a carefully
spaced and current ramped electron pulse train to produce wakefields that increases transformer ratio, a parameter
that characterizes the energy transfer efficiency. A dielectric loaded wakefield structure with 13.625 GHz excitation
frequency was installed in the test section of the AWA. A laser multisplitter is used for multiple bunch generation. In
this experiment, two bunches were used with charge ratio of 1 to 3 nC, and bunch length of 0.2 cm. The wakefield was
measured with an rf pick-up probe. This experimental beam test demonstrated that a bunch train can be generated
with the beam separation in the range of 740 picoseconds required for the maximum transformer ratio to be obtained.
Design and Experimental Investigation of an X-band Multilayer Dielectric Accelerating
Structure
A. Kanareykin, C.-J. Jing (Euclid TechLabs, LLC) W. Gai, J.G. Power
(ANL)
A new project to significantly improve the
efficiency of high gradient DLA structures is
presented. A multilayer DLA where the single
dielectric layer is replaced by a multiple
coaxial layers of differing permittivity have been developed. The power attenuation in the multilayer structure is
reduced by the Bragg Fiber principle where the dielectric layers are used to create multiple reflections in order to
confine the accelerating mode fields for the most part in the dielectric, reducing the axial current on the conducting
outer boundary. A design for an X-band multilayer structure operating in the TM03 mode using alternating dielectric
layers with permittivities of 38 and 9.7 is discussed. In order to transfer the RF from the rectangular waveguide to the
cylindrical one at TM03 mode, a special coupling and mode conversion scheme was developed. A prototype structure
has been constructed and bench test results of the multilayer 11.424 GHz accelerator is presented.
RF Field Measurements and Tuning of the 3 1/2 Cell Cavities and Tuner Test for the
Rossendorf Superconducting RF Electron Gun
D. Janssen, A. Arnold, H. Buettig, R. Hempel, U. Lehnert, P. Michel,
K. Moeller, P. Murcek, Ch. Schneider, R. Schurig, F. Staufenbiel, J.
Teichert, R. Xiang (FZR) T. Kamps, D. Lipka (BESSY GmbH) J.
Stephan (IKST) V. Volkov (BINP SB RAS) I. Will (MBI)
In this paper we report the status and the
progress of the superconducting RF gun
project in Rossendorf. The gun is designed
for cw operation mode with 1 mA current
and 10 MeV electron energy. The cavity consists
of three cells with TESLA geometry, a
special designed half-cell in which the photo cathode will be inserted and a choke filter, which prevents the leakage
of RF power by the coaxial line between the cathode and the cavity cell. A double tuner allows the tuning of the halfcell
and the TESLA cells separately. In 2005 the fabrication of two cavities with RRR300 and RRR40 was finished.
We present the results of the field measurement and the warm tuning of the cavity cells as well as the tuning and
performance measurement of the choke filter. The fabrication of the double tuner has been also finished. In a test
bench we measured the properties of the tuner (tuning range, resolution) at LN2 temperature. Further activities