First Results of the Phase II SIMPLE Dark Matter Search

We report results of a 14.1 kgd measurement with 15 superheated droplet detectors of total active mass 0.208 kg, comprising the first stage of a 30 kgd Phase II experiment. In combination with the results of the neutron-spin sensitive XENON10 experiment, these results yield a limit of |a_p| < 0.32 for M_W = 50 GeV/c2 on the spin-dependent sector of weakly interacting massive particle-nucleus interactions with a 50% reduction in the previously allowed region of the phase space formerly defined by XENON, KIMS and PICASSO. In the spin-independent sector, a limit of 2.3x10-5 pb at M_W = 45 GeV/c2 is obtained.Comment: 4 pages, 4 figures; PRL-accepted version with corrected SI contour (Fig. 4

Final Analysis and Results of the Phase II SIMPLE Dark Matter Search

We report the final results of the Phase II SIMPLE measurements, comprising two run stages of 15 superheated droplet detectors each, the second stage including an improved neutron shielding. The analyses includes a refined signal analysis, and revised nucleation efficiency based on reanalysis of previously-reported monochromatic neutron irradiations. The combined results yield a contour minimum of \sigma_{p} = 4.2 x 10^-3 pb at 35 GeV/c^2 on the spin-dependent sector of WIMP-proton interactions, the most restrictive to date from a direct search experiment and overlapping for the first time results previously obtained only indirectly. In the spin-independent sector, a minimum of 3.6 x 10^-6 pb at 35 GeV/c^2 is achieved, with the exclusion contour challenging the recent CoGeNT region of current interest.Comment: revised, PRL-accepted version with slightly weakened limit contour

The SIMPLE Phase II Dark Matter Search

Phase II of SIMPLE (Superheated Instrument for Massive ParticLe Experiments) searched for astroparticle dark matter using superheated liquid C$_{2}$ClF$_{5}$ droplet detectors. Each droplet generally requires an energy deposition with linear energy transfer (LET) $\gtrsim$ 150 keV/$\mu$m for a liquid-to-gas phase transition, providing an intrinsic rejection against minimum ionizing particles of order 10$^{-10}$, and reducing the backgrounds to primarily $\alpha$ and neutron-induced recoil events. The droplet phase transition generates a millimetric-sized gas bubble which is recorded by acoustic means. We describe the SIMPLE detectors, their acoustic instrumentation, and the characterizations, signal analysis and data selection which yield a particle-induced, "true nucleation" event detection efficiency of better than 97% at a 95% C.L. The recoil-$\alpha$ event discrimination, determined using detectors first irradiated with neutrons and then doped with alpha emitters, provides a recoil identification of better than 99%; it differs from those of COUPP and PICASSO primarily as a result of their different liquids with lower critical LETs. The science measurements, comprising two shielded arrays of fifteen detectors each and a total exposure of 27.77 kgd, are detailed. Removal of the 1.94 kgd Stage 1 installation period data, which had previously been mistakenly included in the data, reduces the science exposure from 20.18 to 18.24 kgd and provides new contour minima of $\sigma_{p}$ = 4.3 $\times$ 10$^{-3}$ pb at 35 GeV/c$^{2}$ in the spin-dependent sector of WIMP-proton interactions and $\sigma_{N}$ = 3.6 $\times$ 10$^{-6}$ pb at 35 GeV/c$^{2}$ in the spin-independent sector. These results are examined with respect to the fluorine spin and halo parameters used in the previous data analysis.Comment: 20 pages, 19 figures; accepted Physical Review

Le Laboratoire Souterrain à Bas Bruit de Rustrel, Pays d’Apt (LSBB)

National audienc

Experimental measurements of the cosmic-ray induced neutron spectra at various mountain altitudes with HERMEIS

Measurements performed with the High Energy Range Multisphere Extended IRSN System (HERMEIS) acquired by the French Aerospace Lab are presented and discussed. The detectors were calibrated at the Low Noise Underground Laboratory of Rustrel. Atmospheric neutron spectra were obtained at three altitudes (+500 m, +1000 m and +2885 m) and the first results about the continuous measurements of the Natural Radiative Environment at the Pic du Midi are presented with a discussion about the uncertainties. © 2012 IEEE

Hydrodynamic organisation of the flows in the unsaturated zone of the Fontaine de Vaucluse karst system. First results

Karst systems contain important groundwater resources. Due to their complexity, they are generally under exploited. Particularly, the hydrodynamic functioning of the unsaturated zone is badly understood even if its important role is admitted Today, the hydrogeologists are agreeing with the important function(s) of the unsaturated zone in karst systems, but today this role(s) is badly characterized. As they are very complex systems, karst aquifers are generally under exploited. It is necessary to progress in the understanding of the functioning of the karst systems and particulary in the functioning of the unsaturated zone in order to develop the corresponding management tools. The study of the unsaturated zone of a karst system needs some access to this part of the aquifer. Speleological access is not sufficient because the major part of the water flows in not humanly enterable drains. The Low-Noise Underground Laboratory of Rustrel- Pays d’Apt (LSBB) is an artificial gallery digged in the unsaturated zone of the Fontaine de Vaucluse karst aquifer catchment area. It intersects arbitrarily the fault networks in depth and then the potential areas of flows through the unsaturated zone. From 2002 to 2009, 61 points where water regularly flows have been identified. For each, flow rate has been periodically monitored. This first global study of the acquired data shows a good relation between flows and geological structures. An organization of flows with depth and geology is also underlined. With increasing depth, flows seem to concentrate from numerous faults networks to a little number of high discontinuities

Hydrodynamic organisation of the flows in the unsaturated zone of the Fontaine de Vaucluse karst system. First results

International audienceKarst systems contain important groundwater resources. Due to their complexity, they are generally under exploited. Particularly, the hydrodynamic functioning of the unsaturated zone is badly understood even if its important role is admitted Today, the hydrogeologists are agreeing with the important function(s) of the unsaturated zone in karst systems, but today this role(s) is badly characterized. As they are very complex systems, karst aquifers are generally under exploited. It is necessary to progress in the understanding of the functioning of the karst systems and particulary in the functioning of the unsaturated zone in order to develop the corresponding management tools. The study of the unsaturated zone of a karst system needs some access to this part of the aquifer. Speleological access is not sufficient because the major part of the water flows in not humanly enterable drains. The Low-Noise Underground Laboratory of Rustrel-Pays d'Apt (LSBB) is an artificial gallery digged in the unsaturated zone of the Fontaine de Vaucluse karst aquifer catchment area. It intersects arbitrarily the fault networks in depth and then the potential areas of flows through the unsaturated zone. From 2002 to 2009, 61 points where water regularly flows have been identified. For each, flow rate has been periodically monitored. This first global study of the acquired data shows a good relation between flows and geological structures. An organization of flows with depth and geology is also underlined. With increasing depth, flows seem to concentrate from numerous faults networks to a little number of high discontinuities

Assessment of squid magnetometers in an underground low-noise environment for detection of sismo-iono-magnetic events. III International conference on superconductivity and magnetism,

International audienc

Earth–ionosphere couplings, magnetic storms, seismic precursors and TLEs: Results and prospects of the [SQUID]2 system in the low-noise underground laboratory of Rustrel-Pays d’Apt.

International audienceHigh sensitivity combined with an ultra-low-noise environment [SQUID]2 magnetometer (Superconducting QUantum Interference Device with Shielding QUalified for Ionosphere Detection) allows the observation of Earth–ionosphere couplings. Namely: – identification of a mesopause resonance mode excitable by P waves or by electric field as during the hour before the Sichuan earthquake (May 2008); – S and T breathing modes of the Earth during quiet magnetic and seismic periods; – worldwide signal integral of magnetic storms including polar contributions; – signals in time correlation with sprites (Transient Luminous Events). These results point to a worldwide network of at least a few stations of a similar typeGrâce à sa sensibilité et son environnement très bas bruit, les couplages Terre–ionosphère sont observables par le magnétomètre [SQUID]2 (Superconducting QUantum Interference Device with Shielding QUalified for Ionosphere Detection). Notamment : – un mode de résonance de la mésopause excitable par les ondes P ou par champ électrique comme dans lmodifier letter apostropheheure précédant le séisme de Sichuan en mai 2008 ; – les modes S et T de respiration du globe pendant des périodes de calme magnétique et sismique ; – lmodifier letter apostropheintégrale mondiale du signal des orages magnétiques y compris les contributions polaires ; – des signaux associés aux sylphes. Ceci permet de modifier d'envisager un réseau mondial de quelques stations de même type

Absolute atom gravimeter at LSBB : a first step toward MIGA

International audienc