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Abstract:

The existence of dark matter in the Universe is well established and various techniques are applied to either directly or indirectly detect this dark matter. Supersymmetry provides a well-motivated candidate, the WIMP, which many direct searches seek to detect. Some of the present dark matter experiments use cryogenic detectors, operating in the mini-Kelvin temperature range. This article introduces the general concept underlying these detectors, discusses the different types of detectors in use and shows how some of the experiments achieve suppression of background by being able to distinguish between nuclear recoil and electron recoil.

Abstract:

We discuss the short- and long-term perspectives of the CRESST (Cryogenic Rare Event Search using Superconducting Thermometers) project and present the current status of the experiment and new results concerning detector development. In the search for elementary particle dark matter, CRESST is presently the most advanced deep underground, low-background, cryogenic facility. The basic technique involved is to search for WIMPs (Weakly Interacting Massive Particles) by the measurement of nonthermal phonons, as created by WIMP-induced nuclear recoils. Combined with our newly developed method for the simultaneous measurement of scintillation light, strong background discrimination is possible, resulting in a substantial increase in WIMP detection sensitivity. This will allow a test of the reported positive evidence for a WIMP signal by the DAMA Collaboration in the near future. In the long term, the present CRESST setup permits the installation of a detector mass up to 100 kg. In contrast to other projects, CRESST technology allows the employment of a large variety of detection materials. This offers a powerful tool in establishing a WIMP signal and in investigating WIMP properties in the event of a positive signal. © 2000 MAIK "Nauka/Interperiodica".

Abstract:

214Po is implanted into surfaces exposed to radon. The implantation rate could be sufficient to explain the rate of low-energy events with anomalously fast scintillation pulses that has been observed in sodium iodide crystals used in a search for WIMP dark matter. The rate should be closely coupled in time to the radon concentration. (C) 2000 Elsevier Science B.V.