Publications (8)0 Total impact
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Article: First Results of the EDELWEISS WIMP Search using a 320 g Heat-and-Ionization Ge Detector
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ABSTRACT: 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. B06/2001; -
Article: The EDELWEISS Experiment : Status and Outlook
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ABSTRACT: 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.02/2001; -
Article: Dark Matter Search in the Edelweiss Experiment
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ABSTRACT: 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.02/2001; -
Article: Status of the EDELWEISS Experiment
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ABSTRACT: The status of the EDELWEISS experiment (underground dark matter search with heat-ionisation bolometers) is reviewed. Auspicious results achieved with a prototype 70 g Ge heat-ionisation detector under a 2 V reverse bias tension are discussed. Based on gamma and neutron calibrations, a best-case rejection factor, over the 15-45 keV range, of 99.7 % for gammas, with an acceptance of 94 % for neutrons, is presented first. Some operational results of physical interest obtained under poor low radioactivity conditions follow. They include a raw event rate of around 30 events/day/kg/keV over the same energy range, and, after rejection of part of the background, lead to a conservative upper limit on the signal of approximately 1.6 events/day/kg/keV at a 90 % confidence level. Performance degrading surface effects of the detector are speculated upon; and planned upgrades are summarized. Comment: 5 pages, 4 eps figures, LaTeX requires espcrc2.sty; Proceedings of TAUP97, Gran Sasso, Italy, September 7-11, 199701/1998; -
Article: First results of the EDELWEISS WIMP search using a 320 g heat-and-ionization Ge detector
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ABSTRACT: 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 day. 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.Physics Letters B. -
Article: Status of the EDELWEISS experiment
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ABSTRACT: The status of the EDELWEISS experiment is presented. Data taking of two prototype detectors tested in the setup designed for the “1 kg” stage show an event rate before rejection of ≈2 evt/kg/keV/day above E > 20 keV, a factor ≈10 improvement compared to previous detectors. An unexpected category of events is evidenced which could explain the anomalous events observed by the UKDMC and Saclay NaI WIMP detection experiments.Nuclear Physics B - Proceedings Supplements. -
Article: Event categories in the EDELWEISS WIMP search experiment
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ABSTRACT: 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 (within ≈10–20 μm 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.Physics Letters B. -
Article: Status of the EDELWEISS experiment
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ABSTRACT: The status of the EDELWEISS experiment, installed in the Fréjus tunnel, is presented. In its first stage, the experiment uses a 70 g high purity Ge bolometer with heat-ionization discrimination. Based on physics data, gamma and neutron calibrations, the influence of inverse bias voltage (−2 and −6 V) on incomplete surface charge collection, which limits at present the performances of these detectors, is presented. Analysing runs with a total exposure of 1.17 kg×day after cuts, an upper limit of 0.6 event day kg keV at 90% confidence level in the 12–70 keV recoil energy interval is obtained. Planned upgrades are summarized.Physics Reports.
