1,597 research outputs found
La Formation de Jupille, nouvelle formation dans le Dévonien inférieur de la Haute-Ardenne (Belgique)
The Jupille Formation, new formation in the lower Devonian of the High-Ardenne (Belgium). A new formation named Jupille is proposed to better characterize in the High-Ardenne area the rocks interbedded between the La Roche (or Villé if La Roche is missing) and PÚrnelle Formations, at the transition between the Pragian/Emsian stages (Lower Devonian). This formation is made up of series of grey, blue grey or greenish grey sandstone layers interbedded in blue grey siltstones and slates similar to those of the La Roche Formation. Locally, the sandstones grades to quartzites. Tool marks, current ripples, lenticular and oblique or hummocky cross-stratifications and load casts (pseudonodules) are present in the sandstone layers
Tunable Superconducting Properties of a-NbSi Thin Films and Application to Detection in Astrophysics
We report on the superconducting properties of amorphous NbxSi1-x thin films.
The normal-state resistance and critical temperatures can be separately
adjusted to suit the desired application. Notably, the relatively low
electron-phonon coupling of these films makes them good candidates for an "all
electron bolometer" for Cosmological Microwave Background radiation detection.
Moreover, this device can be made to suit both high and low impedance readouts
Effect of annealing on the superconducting properties of a-Nb(x)Si(1-x) thin films
a-Nb(x)Si(1-x) thin films with thicknesses down to 25 {\AA} have been
structurally characterized by TEM (Transmission Electron Microscopy)
measurements. As-deposited or annealed films are shown to be continuous and
homogeneous in composition and thickness, up to an annealing temperature of
500{\deg}C. We have carried out low temperature transport measurements on these
films close to the superconductor-to-insulator transition (SIT), and shown a
qualitative difference between the effect of annealing or composition, and a
reduction of the film thickness on the superconducting properties of a-NbSi.
These results question the pertinence of the sheet resistance R_square as the
relevant parameter to describe the SIT.Comment: 9 pages, 12 figure
MicrofaciĂšs dâune lentille biohermale a la limite Eifelien/Givetien (âFondry Des Chiensâ, Nismes, bord sud du synclinorium de Dinant)
Microfacies of a biohermal lens at the Eifelian.Givetian transition (âFondry des Chiensâ, Nismes, southern border of the Dinant Synclinorium). The biohermal lens of the âFondry des Chiensâ belongs to the Eifelian-Givetian transition beds near Nismes (southern flank of the Dinant basin). The lens is 64 m thick and composed of a stromatopore-coral framestone. It is overlain by restricted lagoonal algal and cyanophycean facies near the emersion, and overlies Udoteacean and coral-bryozoan coverstones forming the flanks of two other unexposed lenses. Two crinoidal soles stabilized by syntaxial cementation constitute the substratum of these lenses. The reefal sedimentation is regressive. The log is based on the succession of 10 carbonate microfacies (MF1-10, standard sequence). The deepest microfacies (MF1) is open marine at the upper limit of the storm waves and the dysphotic-euphotic boundary. The shallowest sediments were partly emerged (lagoonal sediments, MF10). The exposed reefal lens (rudstones and framestones, MF6-7) and the flanks (grainstones, floatstones and coverstones, MF3-4-5) of the two other lenses are preserved due to early isopachous intergranular cement in the original cavities of the framestones or âintramicriticâ (replacement of the matrix) cementation in the floatstones and coverstones. The similarity of the facies and their algal content suggest that the sedimentary model proposed at Wellin is applicable at Nismes. Sequential analysis points to a three steps regressive evolution of the sedimentation probably related to a discontinuous subidence. The sequences have similar thicknesses (sixty or so meters) and grade from the dysphotic-euphotic boundary estimated here around twenty meters deep to emersion. As for Wellin, the subsidence is thus much more important than the eustatic regression
Background suppression in massive TeO bolometers with Neganov-Luke amplified light detectors
Bolometric detectors are excellent devices for the investigation of
neutrinoless double-beta decay (0). The observation of such
decay would demonstrate the violation of lepton number, and at the same time it
would necessarily imply that neutrinos have a Majorana character. The
sensitivity of cryogenic detectors based on TeO is strongly limited by the
alpha background in the region of interest for the 0 of
Te. It has been demonstrated that particle discrimination in TeO
bolometers is possible measuring the Cherenkov light produced by particle
interactions. However an event-by-event discrimination with NTD-based light
detectors has to be demonstrated. We will discuss the performance of a
highly-sensitive light detector exploiting the Neganov-Luke effect for signal
amplification. The detector, being operated with NTD-thermistor and coupled to
a 750 g TeO crystal, shows the ability for an event-by-event identification
of electron/gamma and alpha particles. The extremely low detector baseline
noise, RMS 19 eV, demonstrates the possibility to enhance the sensitivity of
TeO-based 0 experiment to an unprecedented level
Niobium Silicon alloys for Kinetic Inductance Detectors
We are studying the properties of Niobium Silicon amorphous alloys as a
candidate material for the fabrication of highly sensitive Kinetic Inductance
Detectors (KID), optimized for very low optical loads. As in the case of other
composite materials, the NbSi properties can be changed by varying the relative
amounts of its components. Using a NbSi film with T_c around 1 K we have been
able to obtain the first NbSi resonators, observe an optical response and
acquire a spectrum in the band 50 to 300 GHz. The data taken show that this
material has very high kinetic inductance and normal state surface resistivity.
These properties are ideal for the development of KID. More measurements are
planned to further characterize the NbSi alloy and fully investigate its
potential.Comment: Accepted for publication on Journal of Low Temperature Physics.
Proceedings of the LTD15 conference (Caltech 2013
Thermally-Stimulated Current Investigation of Dopant-Related D- and A+ Trap Centers in Germanium for Cryogenic Detector Applications
International audienceThermally-stimulated current measurements provide a sensitive tool to char-acterize carrier traps in germanium detectors for dark matter search. Using this technique at cryogenic temperatures, very shallow traps have been detected with binding energies of a fraction of a meV, associated with the dopant species in the D-(A+) charge states. A positive identification of these traps is achieved through an analysis of the field dependence of the carrier emission rates, which demonstrates a potential well for the trapped carriers in the form of a polarization well in r-4, consistent with Lax's model for carrier trapping by a neutral center. The density of these traps is assessed, and implications for the space-charge cancellation procedure in cryogenic Ge detectors are discussed
Pelvic-Floor Rehabilitation, Part 1 : Comparison of Two Surface Electrode Placements During Stimulation of the Pelvic-Floor Musculature in Women Who Are Continent Using Bipolar Interferential Currents
Background and Purpose. Electrical stimulation of the pelvic floor is used as an adjunct in the conservative treatment of urinary incontinence. No consensus exists, however, regarding electrode placements for optimal stimulation of the pelvic-floor musculature. The purpose of this study was to compare two different bipolar electrode placements, one suggested by Laycock and Green (L2) the other by Dumoulin (D2), during electrical stimulation with interferential currents of the pelvic-floor musculature in continent women, using a two-group crossover design. Subjects. Ten continent female volunteers, ranging in age from 20 to 39 years (XÌ
=27.3, SD=5.6), were randomly assigned to one of two study groups. Methods. Each study group received neuromuscular electrical stimulation (NMES) of the pelvic-floor musculature using both electrode placements, the order of application being reversed for each group. Force of contraction was measured as pressure (in centimeters of water [cm H2O]) exerted on a vaginal pressure probe attached to a manometer. Data were analyzed using a two-way, mixed-model analysis of variance. Results. No difference in pressure was observed between the two electrode placements. Differences in current amplitude were observed, with the D2 electrode placement requiring less current amplitude to produce a maximum recorded pressure on the manometer. Subjective assessment by the subjects revealed a preference for the D2 electrode placement (7 of 10 subjects). Conclusion and Discussion. The lower current amplitudes required with the D2 placement to obtain recordings comparable to those obtained with the L2 technique suggest a more comfortable stimulation of the pelvic-floor muscles. The lower current amplitudes required also suggest that greater increases in pressure might be obtained with the D2 placement by increasing the current amplitude while remaining within the comfort threshold. These results will help to define treatment guidelines for a planned clinical study investigating the effects of NMES and exercise in the treatment of urinary stress incontinence in women postpartum
Rejection of randomly coinciding events in LiMoO scintillating bolometers using light detectors based on the Neganov-Luke effect
Random coincidences of nuclear events can be one of the main background
sources in low-temperature calorimetric experiments looking for neutrinoless
double-beta decay, especially in those searches based on scintillating
bolometers embedding the promising double-beta candidate Mo, because of
the relatively short half-life of the two-neutrino double-beta decay of this
nucleus. We show in this work that randomly coinciding events of the
two-neutrino double decay of Mo in enriched LiMoO
detectors can be effectively discriminated by pulse-shape analysis in the light
channel if the scintillating bolometer is provided with a Neganov-Luke light
detector, which can improve the signal-to-noise ratio by a large factor,
assumed here at the level of on the basis of preliminary
experimental results obtained with these devices. The achieved pile-up
rejection efficiency results in a very low contribution, of the order of counts/(keVkgy), to the background counting rate
in the region of interest for a large volume ( cm)
LiMoO detector. This background level is very encouraging in
view of a possible use of the LiMoO solution for a bolometric
tonne-scale next-generation experiment as that proposed in the CUPID project
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