387 research outputs found

    Verliebt – Verlobt – Verheiratet:Wandel der Hochzeit im 20. Jahrhundert

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    Die Entscheidung zu heiraten gilt heute als höchstpersönliche Angelegenheit des Brautpaares und Grundstein ihres individuellen Glücks. Doch wenn ein Paar heiratet, ist das nicht nur eine private Entscheidung. Die Brautleute sind immer auch Einflüssen aus Elternhaus, Kirche, Gesamtgesellschaft und Staat ausgesetzt und wirken ihrerseits mit ihrer Entscheidung auf diese Institutionen zurück. Änderungen im Heiratsverhalten stellen somit einen wichtigen Indikator für gesellschaftliche Entwicklungen dar. Um diese Entwicklungen erfassen und darstellen zu können, hat eine Gruppe von acht Teilnehmerinnen und Teilnehmern des Studiums im Alter an der Universität Münster, die Geschichte der Hochzeit im 20. Jahrhundert im Vergleich der Hochzeitsgenerationen der Studierenden (Heirat 1960-75), ihrer Eltern (Heirat 1930-45) und Großeltern (Heirat 1900-1915) untersucht. Hierzu recherchierte die Gruppe in Archiven und Bibliotheken und wertete 586 für das Projekt entwickelte, standardisierte Fragebögen aus

    A search for low-mass WIMPs with EDELWEISS-II heat-and-ionization detectors

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    We report on a search for low-energy (E < 20 keV) WIMP-induced nuclear recoils using data collected in 2009 - 2010 by EDELWEISS from four germanium detectors equipped with thermal sensors and an electrode design (ID) which allows to efficiently reject several sources of background. The data indicate no evidence for an exponential distribution of low-energy nuclear recoils that could be attributed to WIMP elastic scattering after an exposure of 113 kg.d. For WIMPs of mass 10 GeV, the observation of one event in the WIMP search region results in a 90% CL limit of 1.0x10^-5 pb on the spin-independent WIMP-nucleon scattering cross-section, which constrains the parameter space associated with the findings reported by the CoGeNT, DAMA and CRESST experiments.Comment: PRD rapid communication accepte

    Final results of the EDELWEISS-II WIMP search using a 4-kg array of cryogenic germanium detectors with interleaved electrodes

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    The EDELWEISS-II collaboration has completed a direct search for WIMP dark matter with an array of ten 400-g cryogenic germanium detectors in operation at the Laboratoire Souterrain de Modane. The combined use of thermal phonon sensors and charge collection electrodes with an interleaved geometry enables the efficient rejection of gamma-induced radioactivity as well as near-surface interactions. A total effective exposure of 384 kg.d has been achieved, mostly coming from fourteen months of continuous operation. Five nuclear recoil candidates are observed above 20 keV, while the estimated background is 3.0 events. The result is interpreted in terms of limits on the cross-section of spin-independent interactions of WIMPs and nucleons. A cross-section of 4.4x10^-8 pb is excluded at 90%CL for a WIMP mass of 85 GeV. New constraints are also set on models where the WIMP-nucleon scattering is inelastic.Comment: 23 pages, 5 figures; matches published versio

    Background studies for the EDELWEISS dark matter experiment

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    The EDELWEISS-II collaboration has completed a direct search for WIMP dark matter using cryogenic Ge detectors (400 g each) and 384 kg×\timesdays of effective exposure. A cross-section of 4.4×1084.4 \times 10^{-8} pb is excluded at 90% C.L. for a WIMP mass of 85 GeV. The next phase, EDELWEISS-III, aims to probe spin-independent WIMP-nucleon cross-sections down to a few ×109\times10^{-9} pb. We present here the study of gamma and neutron background coming from radioactive decays in the set-up and shielding materials. We have carried out Monte Carlo simulations for the completed EDELWEISS-II setup with GEANT4 and normalised the expected background rates to the measured radioactivity levels (or their upper limits) of all materials and components. The expected gamma-ray event rate in EDELWEISS-II at 20-200 keV agrees with the observed rate of 82 events/kg/day within the uncertainties in the measured concentrations. The calculated neutron rate from radioactivity of 1.0-3.1 events (90% C.L.) at 20-200 keV in the EDELWEISS-II data together with the expected upper limit on the misidentified gamma-ray events (0.9\le0.9), surface betas (0.3\le0.3), and muon-induced neutrons (0.7\le0.7), do not contradict 5 observed events in nuclear recoil band. We have then extended the simulation framework to the EDELWEISS-III configuration with 800 g crystals, better material purity and additional neutron shielding inside the cryostat. The gamma-ray and neutron backgrounds in 24 kg fiducial mass of EDELWEISS-III have been calculated as 14-44 events/kg/day and 0.7-1.4 events per year, respectively. The results of the background studies performed in the present work have helped to select better purity components and improve shielding in EDELWEISS-III to further reduce the expected rate of background events in the next phase of the experiment.Comment: 15 pages, 9 figures, to be published in Astroparticle Physic

    Muon-induced background in the EDELWEISS dark matter search

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    A dedicated analysis of the muon-induced background in the EDELWEISS dark matter search has been performed on a data set acquired in 2009 and 2010. The total muon flux underground in the Laboratoire Souterrain de Modane (LSM) was measured to be Φμ=(5.4±0.20.9+0.5)\Phi_{\mu}=(5.4\pm 0.2 ^{+0.5}_{-0.9})\,muons/m2^2/d. The modular design of the muon-veto system allows the reconstruction of the muon trajectory and hence the determination of the angular dependent muon flux in LSM. The results are in good agreement with both MC simulations and earlier measurements. Synchronization of the muon-veto system with the phonon and ionization signals of the Ge detector array allowed identification of muon-induced events. Rates for all muon-induced events Γμ=(0.172±0.012)evts/(kgd)\Gamma^{\mu}=(0.172 \pm 0.012)\, \rm{evts}/(\rm{kg \cdot d}) and of WIMP-like events Γμn=0.0080.004+0.005evts/(kgd)\Gamma^{\mu-n} = 0.008^{+0.005}_{-0.004}\, \rm{evts}/(\rm{kg \cdot d}) were extracted. After vetoing, the remaining rate of accepted muon-induced neutrons in the EDELWEISS-II dark matter search was determined to be Γirredμn<6104evts/(kgd)\Gamma^{\mu-n}_{\rm irred} < 6\cdot 10^{-4} \, \rm{evts}/(\rm{kg \cdot d}) at 90%\,C.L. Based on these results, the muon-induced background expectation for an anticipated exposure of 3000\,\kgd\ for EDELWEISS-3 is N3000kgdμn<0.6N^{\mu-n}_{3000 kg\cdot d} < 0.6 events.Comment: 21 pages, 16 figures, Accepted for publication in Astropart. Phy

    Axion searches with the EDELWEISS-II experiment

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    We present new constraints on the couplings of axions and more generic axion-like particles using data from the EDELWEISS-II experiment. The EDELWEISS experiment, located at the Underground Laboratory of Modane, primarily aims at the direct detection of WIMPs using germanium bolometers. It is also sensitive to the low-energy electron recoils that would be induced by solar or dark matter axions. Using a total exposure of up to 448 kg.d, we searched for axion-induced electron recoils down to 2.5 keV within four scenarios involving different hypotheses on the origin and couplings of axions. We set a 95% CL limit on the coupling to photons gAγ<2.13×109g_{A\gamma}<2.13\times 10^{-9} GeV1^{-1} in a mass range not fully covered by axion helioscopes. We also constrain the coupling to electrons, gAe<2.56×1011g_{Ae} < 2.56\times 10^{-11}, similar to the more indirect solar neutrino bound. Finally we place a limit on gAe×gANeff<4.70×1017g_{Ae}\times g_{AN}^{\rm eff}<4.70 \times 10^{-17}, where gANeffg_{AN}^{\rm eff} is the effective axion-nucleon coupling for 57^{57}Fe. Combining these results we fully exclude the mass range 0.91eV<mA<800.91\,{\rm eV}<m_A<80 keV for DFSZ axions and 5.73eV<mA<405.73\,{\rm eV}<m_A<40 keV for KSVZ axions
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