C. Goldbach

First results of the EDELWEISS WIMP search using a 320 g heat-and-ionization Ge detector

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.

Dark matter search with a low temperature sapphire bolometer

Abstract A dark matter detection experiment using a low temperature 24 g sapphire bolometer is presented. The low radioactive background cryogenic facility, installed in a deep underground site, is described, as well as the low-noise read-out electronics and the data analysis. From the energy spectrum, measured down to 4 keV, exclusion plots are derived for WIMPs having coherent vector coupling or axial coupling to ordinary matter.

Identification of backgrounds in the EDELWEISS-I dark matter search experiment

Abstract 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.

Calibration of the EDELWEISS cryogenic heat-and-ionization germanium detectors for dark matter search

Several aspects of the analysis of the data obtained with the cryogenic heat-and-ionization Ge detectors used by the EDELWEISS dark matter search experiment are presented. Their calibration, the determination of their energy threshold, fiducial volume and nuclear recoil acceptance are detailed.

Sensitivity of the EDELWEISS WIMP search to spin-dependent interactions

The EDELWEISS collaboration is searching for WIMP dark matter using natural Ge cryogenic detectors. The whole data set of the first phase of the experiment contains a fiducial exposure of 4.8 kg.day on Ge-73, the naturally present (7.8%), high-spin Ge isotope. The sensitivity of the experiment to the spin-dependent WIMP-nucleon interactions is evaluated using the model-independent framework proposed by Tovey et al.

Event categories in the EDELWEISS WIMP search experiment

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.

Bolometric detection of the recoil spectrum in the alpha decay of 210Po

Abstract Bolometers at low temperature are being developed as particle spectrometers and potential detectors of dark matter particles through the measurement of recoil energies. A successful observation of the recoil spectrum from a 210 Po electrodeposited source was made for the first time with the use of a 2 mm 3 composite-composite diamond bolometer operated in a 300 mK cryostat. The measured recoil ratio is 0.98±0.06 recoil/alpha above 50 keV, with the well defined peak in the spectrum at 101±2.5 keV.

Dark matter search in the Fréjus Underground Laboratory EDELWEISS experiment

Abstract The status of the EDELWEISS experiment (Experience pour DEtecter Les Wimps En SIte Souterrain) in the Frejus Underground Laboratory is reported. The cryostat is described with the main lines of low radioactivity design and readout system. The first results using bolometer detectors together with the measurement of the internal radioactive background using a 100 cm 3 classical Ge crystal are reported. The future program of the experiment will be outlined.

Towards measurement of recoils below 4 keV with the ⪡ROSEBUD⪢ experiment

Abstract An experiment to look for light WIMPs with sapphire bolometers is to be installed in the Canfranc Underground Laboratory (at 2450 m.w.e) in the Spanish Pyrenees. In the first stage two small 25g bolometers with NTD-Ge sensors, operating at 25mK, with an energy threshold of 300eV and FWHM energy resolution of 120eV at 1.5keV will perform a background test experiment. The features of the bolometers, the radioactivity measurements of the components and the set-up and status of the experiment are reported.

First results of the EDELWEISS experiment

The ethical question about the information technologies We refer here to Aristotles definition of ethics to illuminate some practices generated by information technology. For example, the accumulation of documents (temptation to “possess” resources ), the problem of incorporating user – generated information within the project phases (problem of integrating alternative approaches), the assertion about the absolute freedom to make use of the ideas accessible on the web (the individuals interest takes precedence over laws of property); the decisive significance imputed to knowledge as opposed to imagination or affectivity. The denial of the corporeal in the world of the intellect is a philosophical point of view with its roots deep in gnosticism.