The EDELWEISS Experiment : Status and Outlook

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.Comment: International Conference on Dark Matter in Astro and Particle Physics (Dark 2000), Heidelberg, Germany, 10-16 Jul 2000, v3 minor revision

Physical interpretation of the Neganov\u2013Luke and related effects

The Neganov\u2013Luke effect consists mainly of the enhancement of heat deposited by an ionizing particle in a bolometer at low temperatures, when the induced charges are collected by an applied voltage. The paper will present a detailed explanation of this phenemenon and its magnitude

320 g ionization-heat bolometers design for the EDELWEISS experiment

To achieve a high level of discrimination between nuclear recoils and radioactive background, a new in size 320 g ionization\u2013heat bolometer has been designed and realized for the EDELWEISS experiment. With this new device we are expecting a great improvement in background limitation in particular for betas and low-energy X- and \u3b3-rays. Sensitivities to Luke effect and infrared source are also discussed

A sparkless resistive glass correction electrode for the spherical proportional counter

International audienceA new anode support structure for the spherical proportional counter is presented that incorporates a resistive correction electrode made of glass. This electrode improves the electric field homogeneity versus angle, while suppressing the probability and intensity of sparks compared to non-resistive alternatives. The configuration of the correction electrode was optimised with simulations. Such support structures have been constructed and measurements have demonstrated homogeneous response of the detector and operational stability. A measurement of the resistivity of the glass used is also presented

A Low Background Setup for Low Energy X-ray Detection in the Context of the BabyIAXO/IAXO Axion Searches

International audienceIn the context of axion search in the BabyIAXO and IAXO helioscopes, various types of cryogenic detectors are investigated as high energy resolution, low energy threshold alternatives for the standard micromegas X-ray detectors. The setup presented in this paper comprising metallic magnetic calorimeter (MMC) X-ray detectors, a cryogenic local muon veto read out by an MMC, and internal and external lead shields, aims at establishing the background level that can be reached with MMCs in an above-ground experimental site. The low background setup is described in detail, and first observations from a low-temperature run are presented

A multiball read-out for the spherical proportional counter

International audienceWe present a novel concept of proportional gas amplification for the read-out of the spherical proportional counter. The standard single-ball read-out presents limitations for large diameter spherical detectors and high-pressure operations. We have developed a multi-ball read-out system which consists of several balls placed at a fixed distance from the center of the spherical vessel. Such a module can tune the volume electric field at the desired value and can also provide detector segmentation with individual ball read-out. In the latter case, the large volume of the vessel becomes a spherical time projection chamber with 3D capabilities

The First Tests of a Large-Area Light Detector Equipped with Metallic Magnetic Calorimeters for Scintillating Bolometers for the LUMINEU Neutrinoless Double Beta Decay Search

International audienceFuture rare-event searches using scintillating crystals need very low background levels for high sensitivity, however, unresolved pile-up can limit this. We present the design and fabrication of large-area photon detectors based on metallic magnetic calorimeters (MMCs), optimized for fast rise times to resolve close pile-up. The first prototypes have been characterized using Fe-55 X-rays and ZnMoO$_{4}$ crystal scintillation light. A fast intrinsic rise time of 25–30  \upmu s has been measured and has been compared to the 250  \upmu s scintillation light pulse rise time constant. The difference indicates that the scintillation process limits the light pulse rise time. The fast rise time allows for a reduction of background due to close pile-up events as well as the study of the inherent crystal scintillation process. MMC-based photon detectors are shown to be a promising tool for scintillating crystal based rare event searches