572 research outputs found
A piecewise-linear reduced-order model of squeeze-film damping for deformable structures including large displacement effects
This paper presents a reduced-order model for the Reynolds equation for
deformable structure and large displacements. It is based on the model
established in [11] which is piece-wise linearized using two different methods.
The advantages and drawbacks of each method are pointed out. The pull-in time
of a microswitch is determined and compared to experimental and other
simulation data.Comment: Submitted on behalf of EDA Publishing Association
(http://irevues.inist.fr/handle/2042/16838
Exoplanet Imaging Data Challenge, phase II: Characterization of exoplanet signals in high-contrast images
Today, there exists a wide variety of algorithms dedicated to high-contrast
imaging, especially for the detection and characterisation of exoplanet
signals. These algorithms are tailored to address the very high contrast
between the exoplanet signal(s), which can be more than two orders of magnitude
fainter than the bright starlight residuals in coronagraphic images. The
starlight residuals are inhomogeneously distributed and follow various
timescales that depend on the observing conditions and on the target star
brightness. Disentangling the exoplanet signals within the starlight residuals
is therefore challenging, and new post-processing algorithms are striving to
achieve more accurate astrophysical results. The Exoplanet Imaging Data
Challenge is a community-wide effort to develop, compare and evaluate
algorithms using a set of benchmark high-contrast imaging datasets. After a
first phase ran in 2020 and focused on the detection capabilities of existing
algorithms, the focus of this ongoing second phase is to compare the
characterisation capabilities of state-of-the-art techniques. The
characterisation of planetary companions is two-fold: the astrometry (estimated
position with respect to the host star) and spectrophotometry (estimated
contrast with respect to the host star, as a function of wavelength). The goal
of this second phase is to offer a platform for the community to benchmark
techniques in a fair, homogeneous and robust way, and to foster collaborations.Comment: Submitted to SPIE Astronomical Telescopes + Instrumentation 2022,
Adaptive Optics Systems VIII, Paper 12185-
The EDELWEISS Experiment : Status and Outlook
The EDELWEISS Dark Matter search uses low-temperature Ge detectors with heat
and ionisation read- out to identify nuclear recoils induced by elastic
collisions with WIMPs from the galactic halo. Results from the operation of 70
g and 320 g Ge detectors in the low-background environment of the Modane
Underground Laboratory (LSM) are presented.Comment: International Conference on Dark Matter in Astro and Particle Physics
(Dark 2000), Heidelberg, Germany, 10-16 Jul 2000, v3 minor revision
Dark Matter Search in the Edelweiss Experiment
Preliminary results obtained with 320g bolometers with simultaneous
ionization and heat measurements are described. After a few weeks of data
taking, data accumulated with one of these detectors are beginning to exclude
the upper part of the DAMA region. Prospects for the present run and the second
stage of the experiment, EDELWEISS-II, using an innovative reversed cryostat
allowing data taking with 100 detectors, are briefly described.Comment: IDM 2000, 3rd International Workshop on the Identification of Dark
Matter, York (GB), 18-22/09/2000, v2.0 minor modification
SICANE: a Detector Array for the Measurement of Nuclear Recoil Quenching Factors using Monoenergetic Neutron Beam
SICANE is a neutron scattering multidetector facility for the determination
of the quenching factor (ratio of the response to nuclear recoils and to
electrons) of cryogenic detectors used in direct WIMP searches. Well collimated
monoenergetic neutron beams are obtained with inverse (p,n) reactions. The
facility is described, and results obtained for the quenching factors of
scintillation in NaI(Tl) and of heat and ionization in Ge are presented.Comment: 30 pages, Latex, 11 figures. Submitted to NIM
Event categories in the EDELWEISS WIMP search experiment
Four categories of events have been identified in the EDELWEISS-I dark matter
experiment using germanium cryogenic detectors measuring simultaneously charge
and heat signals. These categories of events are interpreted as electron and
nuclear interactions occurring in the volume of the detector, and electron and
nuclear interactions occurring close to the surface of the detectors(10-20 mu-m
of the surface). We discuss the hypothesis that low energy surface nuclear
recoils,which seem to have been unnoticed by previous WIMP searches, may
provide an interpretation of the anomalous events recorded by the UKDMC and
Saclay NaI experiments. The present analysis points to the necessity of taking
into account surface nuclear and electron recoil interactions for a reliable
estimate of background rejection factors.Comment: 11 pages, submitted to Phys. Lett.
First Results of the EDELWEISS WIMP Search using a 320 g Heat-and-Ionization Ge Detector
The EDELWEISS collaboration has performed a direct search for WIMP dark
matter using a 320 g heat-and-ionization cryogenic Ge detector operated in a
low-background environment in the Laboratoire Souterrain de Modane. No nuclear
recoils are observed in the fiducial volume in the 30-200 keV energy range
during an effective exposure of 4.53 kg.days. Limits for the cross-section for
the spin-independent interaction of WIMPs and nucleons are set in the framework
of the Minimal Supersymmetric Standard Model (MSSM). The central value of the
signal reported by the experiment DAMA is excluded at 90% CL.Comment: 14 pages, Latex, 4 figures. Submitted to Phys. Lett.
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