736 research outputs found
Status report of the CERN microwave axion experiment
"Light Shining Through the Wall" experiments can probe the existence of
"axion like particles" through their weak coupling to photons. We have adapted
such an experiment to the microwave regime and constructed the table top
apparatus. This work presents an overview of the experimental setup and then
focuses on our latest measurement run and its results. By operating the
apparatus within a superconducting MRI magnet, competitive exclusion limits for
axion like particles to the first generation optical light shining through the
wall experiments have been achieved.Comment: Contributed to the 9th Patras Workshop on Axions, WIMPs and WISPs,
Mainz, June 24-28, 201
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
The FPGA-based Continious FFT Tune Measurement System for the LHC and its test at the CERN SPS
A base band tune (BBQ) measurement system has been developed at CERN. This system is based on a high-sensitivity direct-diode detection technique followed by a high resolution FFT algorithm implemented in an FPGA. The system allows acquisition of continuous real-time spectra with 32-bit resolution, while a digital frequency synthesiser (DFS) can provide an acquisition synchronised chirp excitation. All the implemented algorithms support dynamic reconfiguration of processing and excitation parameters. Results from both laboratory measurements and tests performed with beam at the CERN SPS are presented
Locating, and Utilising \u3cem\u3eFestuca Pratensis\u3c/em\u3e Genes for Winter Hardiness for the Future Development of More Persistent High Quality \u3cem\u3eLolium\u3c/em\u3e Cultivars
Genes for freezing-tolerance and winter hardiness were located in Festuca pratensis by QTL analysis and introgression-mapping. QTL for freezing-tolerance on F. pratensis chromosome 4 were orthologous to rice chromosome 3, and Triticeae chromosome 5. Increased energy dissipation during the autumn through a lower maximum quantum yield of photosystem II (PSII) was correlated with improved winter survival. Freezing tolerance in Lolium was achieved by the transfer and subsequent expression of F. pratensis genes from chromosome 4 that govern the expression of a non-photochemical (NPQ) mechanism for the dissipation of excess light energy under low temperature
Karlsruhe institute of technology (KIT)
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 ”Hz range) homodyne detection method is used to reveal the axion signal from background thermal noise. The current status of the experiment is presented
LIBS experiments for quantitative detection of retained fuel
Abstract Laser Induced Breakdown Spectroscopy (LIBS) provides chemical information from atomic and ionic plasma emissions generated by laser vaporization of a sample. At the ENEA research center, in collaboration with IPPLM, an equipment has been set up to qualitatively and quantitatively determine the chemical composition of impurities deposited on Plasma Facing Components (PFC). The strength of the LIBS, for its capability of light elements detection, is fully exploited to determine the deuterium content since this element can be considered as the best choice proxy for tritium; the latter being is of great importance in assessing safe conditions to assure the continuous operation in nuclear fusion tokamak. Here we present the results of the Double Pulse LIBS (DP-LIBS) probing of deuterated samples with the simultaneous optical detection by medium-resolution and high-resolution spectrometer. Deuterium emission at 656.1 nm has been detected then the elemental composition has been quantified by applying the Calibration Free (CF) approach. The obtained results demonstrate that the DP-LIBS technique combined with CF analysis is suitable for the quantitative determination of tritium content inside the PFCs of next fusion devices like ITER
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