We report the final results of EDELWEISS-II, obtained with ten 400 g heat-and-ionization cryogenic detectors equipped with InterDigit electrodes for the rejection of near-surface events. Results from ...fourteen months of continuous operation and a total exposure of 384 kg day are presented. We also present the status of EDELWEISS-III, which will accumulate more than 3000 kg day of data with 40 new 800 g detectors in the coming years.
A multi-tiered data structure, analysis toolkit and data processing management system has been constructed using ROOT and CouchDB. This system is well suited for experiments that acquire many ...computer files of raw data over the course of months or years, that are distributed to different computing centers and further reduced in size by several steps of data processing. Data handling for experiments searching for rare events extracted from digitized pulse traces typically fit this description. An implementation of this system has been constructed for the EDELWEISS-III experiment and is described here in some detail. This solution may also serve as a prototype system for the proposed EURECA experiment.
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.
Muon-induced neutrons constitute a prominent background component in a number of low count rate experiments, namely direct searches for dark matter. In this work we describe a neutron detector to ...measure this background in an underground laboratory, the Laboratoire Souterrain de Modane. The system is based on 1
m
3 of Gd-loaded scintillator and it is linked with the muon veto of the EDELWEISS-II experiment for coincident muon detection. The system was installed in autumn 2008 and passed since then a number of commissioning tests proving its full functionality. The data-taking is continuously ongoing and a count rate of the order of 1 muon-induced neutron per day has been achieved.
This paper presents our interpretation and understanding of the different backgrounds in the EDELWEISS-I data sets. We analyze in detail the several populations observed, which include gammas, ...alphas, neutrons, thermal sensor events and surface events, and try to combine all data sets to provide a coherent picture of the nature and localization of the background sources. In light of this interpretation, we draw conclusions regarding the background suppression scheme for the EDELWEISS-II phase.
Test experiments have been performed on a Ge detector of the Edelweiss collaboration, combining time-resolved acquisition of the ionization signals with heat measurements. Pulse-shape analysis of the ...charge signals demonstrates the capability to reject surface events of poor charge collection with energies larger than 50
keV in ionization.
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.
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