0000000001300956
AUTHOR
M. Stern
Interpretation of the Anomalous NaI Events
Anomalous events, with scintillation decay times shorter than nuclear recoils, have been observed by the UKDMC and Saclay NaI experiments. By using the event categories observed in the EDELWEISS experiment, we propose to interpret the anomalous NaI events as surface nuclear recoils accompanied with a small energy loss of an escaping alpha particle. The discrimination performances of the NaI experiments which have not taken into account these events in their analysis, notably for axial WIMP interactions, must then be reevaluated.
Status of the EDELWEISS experiment
The Edelweiss Dark Matter Experiment is installed in the Modane Underground Laboratory since 1994. In 1997 the first detector of a 70 g heat and ionization Ge low-temperature detector built by the collaboration showed its discrimination capabilities. During the last two years the installation was upgraded, and a new generation of 70 g Ge detectors is operational. The detector environment is drastically controlled to avoid radioactive contamination. A test run with two new 70 g detectors shows a reduction by a factor of ten in the background level before 7-ray rejection which is now around 2 events/kg/keV/day. Three 320 g Ge cryogenic detectors have been constructed and are now being tested …
The XENON1T Dark Matter Experiment
The XENON1T experiment at the Laboratori Nazionali del Gran Sasso (LNGS) is the first WIMP dark matter detector operating with a liquid xenon target mass above the ton-scale. Out of its 3.2 t liquid xenon inventory, 2.0 t constitute the active target of the dual-phase time projection chamber. The scintillation and ionization signals from particle interactions are detected with low-background photomultipliers. This article describes the XENON1T instrument and its subsystems as well as strategies to achieve an unprecedented low background level. First results on the detector response and the performance of the subsystems are also presented. © 2017, The Author(s).
Background discrimination capabilities of a heat and ionization germanium cryogenic detector
The discrimination capabilities of a 70 g heat and ionization Ge bolometer are studied. This first prototype has been used by the EDELWEISS Dark Matter experiment, installed in the Laboratoire Souterrain de Modane, for direct detection of WIMPs. Gamma and neutron calibrations demonstrate that this type of detector is able to reject more than 99.6% of the background while retaining 95% of the signal, provided that the background events distribution is not biased towards the surface of the Ge crystal. However, the 1.17 kg.day of data taken in a relatively important radioactive environment show an extra population slightly overlapping the signal. This background is likely due to interactions o…
CCDC 689904: Experimental Crystal Structure Determination
Related Article: J.Lloret, M.Stern, F.Estevan, M.Sanau, M.A.Ubeda|2008|Organometallics|27|850|doi:10.1021/om700612m