Abstracts Brochure - CERN

WEPLS — Poster Session 28-Jun-06 16:00 - 18:00
or accelerating tubes should be divided into several small segments, in which the iteration procedures are applied.
The results were coded and applied to the calculations of an electrostatic accelerating system.
Design of Diamond-lined Accelerator Structure Test Cavity
For a high-gradient normal-conducting accelerator
structure for a future multi-TeV linear
collider, the main limitation to achievement
of high acceleration gradient is RF
C. Wang, V.P. Yakovlev (Omega-P, Inc.) J.L. Hirshfield (Yale University,
Physics Department)
breakdown. In an attempt to increase the gradient beyond limits that are acceptable for metallic structures, a diamond-lined
structure is suggested. The published DC breakdown limit for CVD diamond is ∼2 GV/m, but the
limit has never been determined for RF fields. Here we present a design for a 34-GHz diamond-lined rectangular test
cavity, operating in the symmetric LSM-1,1,6 mode with symmetric side input couplers. The goal is to produce as
high electric fields as possible (approaching 1 GV/m) at the diamond surfaces with ∼10 MW of input power supplied
by the Omega-P/Yale 34-GHz magnicon for experiment test of dielectric strength.
Developments on a Diamond-based Cylindrical Dielectric Accelerating Structure
Developments on a high gradient diamondbased
cylindrical dielectric loaded accelerator
(DLA) is presented. A diamond-loaded
DLA can potentially sustain accelerating gra-
A. Kanareykin, C.-J. Jing (Euclid TechLabs, LLC) M.E. Conde, W.
Gai, J.G. Power (ANL) P. Schoessow (Tech-X)
dients far in excess of the limits experimentally observed for conventional metallic accelerating structures. The electrical
and mechanical properties of diamond make it an ideal candidate material for use in dielectric accelerators:
high RF breakdown level, extremely low dielectric losses and the highest available thermoconductive coefficient. We
used the hot-filament Chemical Vapor Deposition (CVD) process to produce high quality 5-10 cm long cylindrical
diamond layers. Our collaboration has also been developing a new method of CVD diamond surface preparation
that reduces the secondary electron emission coefficient below unity. Special attention was paid to the numerical
optimization of the coupling section, where the surface magnetic and electric fields were minimized relative to the
accelerating gradient and within known metal surface breakdown limits.
Progress towards an Experimental Test of an Active Microwave Medium Based Accelerator
We have been working on an experimental
test of the PASER concept, where an active
medium is used to provide the energy for
accelerating charged particles. Initial theo-
A. Kanareykin (Euclid TechLabs, LLC) P. Schoessow (Tech-X) L.
Schächter (Technion)
retical work in this area focused on acceleration at optical frequencies; however we have identified a candidate active
material operating in the X-band: a solution of fullerene (C60) in a nematic liquid crystal has been found to exhibit
a maser transition* in this frequency range. The ability to employ a microwave frequency material simplifies the
construction of test structures and allows beam experiments to be performed with relatively large beam emittances.
We will report results on synthesis and testing of the active material using EPR spectroscopy, design and numerical
simulations of bench test structures and plans for future beam experiments.
*A. Blank et al. IEEE Trans. Microwave Theory and Techniques 46 (2137) 1998.
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