Hans Kraus

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 non-thermal 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. © 1999 Elsevier Science B.V. All rights reserved. PACS: 95.35+d; 29.40.

Abstract:

The CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) experiment at the Gran Sasso Laboratory will search for dark matter WIMPs using cryogenic detectors. In the first stage we will use four 262 g sapphire crystals with thresholds of about 0.5 keV. This low threshold gives us sensitivity to WIMP masses below 10 GeV, making CRESST complementary to other dark matter searches. The main installation in Gran Sasso is now complete and we report on the first detector tests.

Abstract:

Cryodetectors with superconducting sensors have been actively developed and optimized during the past years. This review discusses the operating principles of the two detector concepts, superconducting tunnel junctions and low-temperature bolometer or calorimeter. Progress in research with cryodetectors manifested itself by many successful device demonstrations and as a result, a shift in emphasis from pure detector optimization towards actual applications has been observed. Cryodetectors have been used for X-ray fluorescence, optical photon detection, mass spectroscopy of heavy molecules, etc. Nevertheless, there is still room for further improvement until the detectors will have actually reached their theoretical limitations.

Abstract:

Superconducting bolometers and calorimeters are used in many applications, such as infrared astronomy, fast spectroscopy of condensed matter excitations or even in particle physics and plasma diagnostics. The development in this field has a long history and is very active and numerous successful applications can be counted. Many of the detectors discussed in this article make use of the steepness of the resistance-temperature characteristics at the transition between the normal and superconducting phase of superconductors. This overview includes low-TC calorimeters, mainly for applications to particle and astrophysics, and high-TC bolometers which could replace presently used detectors. In addition, related detection techniques will be addressed.