1,119 research outputs found
Status report of the CERN light shining through the wall experiment with microwave axions and related aspects
One way to proof or exclude the existence of axion like particles is a
microwave light shining through the wall experiment. In this publication we
will emphasize on the engineering aspects of such a setup, currently under
development at CERN. One critical point, to achieve meaningful results, is the
electromagnetic shielding between axion-emitter and -receiver cavity, which
needs to be in the order of 300 dB to improve over existing experimental
bounds. The RF leakage or electromagnetic crosstalk between both cavities must
be well controlled and quantified during the complete duration of the
experiment. A very narrow band (in the 10^-6 Hz range) homodyne detection
method is used to reveal the axion signal from background thermal noise. The
current status of the experiment is presented.Comment: Contributed to the "7th Patras Workshop on Axions, WIMPs and WISPs",
Mykonos June 26 - July 1 201
Status report and first results of the microwave LSW experiment at CERN
To detect or exclude the existence of hidden sector photons or axion like
particles, a table-top "microwaves shining through the wall" experiment has
been set up at CERN. An overview of the experimental layout is given, the
technical challenges involved are reviewed and the measurement procedure
including data-evaluation and its results to date are shown.Comment: Contributed to the 8th Patras Workshop on Axions, WIMPs and WISPs,
Chicago, July 18-22, 201
First results of the CERN Resonant WISP Search (CROWS)
The CERN Resonant WISP Search (CROWS) probes the existence of Weakly
Interacting Sub-eV Particles (WISPs) like axions or hidden sector photons. It
is based on the principle of an optical light shining through the wall
experiment, adapted to microwaves. Critical aspects of the experiment are
electromagnetic shielding, design and operation of low loss cavity resonators
and the detection of weak sinusoidal microwave signals. Lower bounds were set
on the coupling constant GeV for axion like
particles with a mass of eV. For hidden sector photons, lower
bounds were set for the coupling constant at a mass
of eV. For the latter we were probing a previously
unexplored region in the parameter space
Extended Classical Over-Barrier Model for Collisions of Highly Charged Ions with Conducting and Insulating Surfaces
We have extended the classical over-barrier model to simulate the
neutralization dynamics of highly charged ions interacting under grazing
incidence with conducting and insulating surfaces. Our calculations are based
on simple model rates for resonant and Auger transitions. We include effects
caused by the dielectric response of the target and, for insulators, localized
surface charges. Characteristic deviations regarding the charge transfer
processes from conducting and insulating targets to the ion are discussed. We
find good agreement with previously published experimental data for the image
energy gain of a variety of highly charged ions impinging on Au, Al, LiF and KI
crystals.Comment: 32 pages http://pikp28.uni-muenster.de/~ducree
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