2)Seach for direct WIMP detection using bolometers (15 mn)

Jules Gascon gascon@ipnl.in2p3.fr Institut de Physique Nuclaire Lyon Universite Claude Bernard 43, Boulevard du 11 Novembre 1918 69622 Villeurbanne Cedex France

Dark Matter Searches with Cryogenic Detectors" Astronomical and cosmological observations suggest that a large fraction of matter in the universe could be in the form of Weakly Interacting Massive Particles (WIMP). In this scenario, the earth would be traversed by a large flux of WIMPs, unobserved so far because of their very small interaction probability with ordinary matter. These rare elastic collisions -- less than one per day per kilo of matter are expected -- would deposit only a few tens of keV. Among the detectors competing in the quest for this elusive particle, those based on bolometer technology are particularly promising. Some of the best WIMP sensitivities are obtained with bolometers where the heat measurement is combined with a measurement of the ionisation produced by WIMP-induced nuclear recoils. The present status and future developments of experiments using bolometers for the search of WIMP dark matter will be presented.

4) Cryogenic detectors for macromolecule mass spectrometer applications (15 mn)

Damian Twerenbold twerenbold@genspec.ch Institut de Physique Rue A.-L.Breguet 1 CH-2000 Neuchâtel, Switzerland

We have introduced cryogenic detectors as single molecule counting detectors in time-of-flight mass spectrometry. Conventionally, secondary electron emission ionizing detectors are used to measure the arrival times of molecules. These ionizing detectors, however, are known to show a strong decrease in quantum efficiency for molecules with decreasing velocity. i.e. for molecules with increasing mass. Cryodetectors measure the energy deposition of a single molecule. Because the kinetic energy of a molecule in a time-of-flight mass spectrometer is the product of the molecule charge and the acceleration voltage, the detection sensitivity of a CryoDetector does not depend on molecule mass. In addition, it can be demonstrated that the quantumefficiency of CryoDetectors for molecules is 100%. Owing to the calorimetric nature of molecule detection, a cryodetector signal carries information about the total energy of the molecule. One can therefore distinguish between the charged states of the molecules, and the molecular background can be reduced by discarding events which do not have the required total kinetic energy, owing to fragmentation or loss of charge during acceleration or free flight. We will present experimental data from a variety of massive macromolecules using different types of cryodetectors. An increase in intrinsic detection efficiency of several orders of magnitude has been demonstrated for massive molecules beyond 50 to 100 kDa.

5) Cryogenic X-Ray detectors for material analysis. (15mn)

Godehard Angloher angloher@paule.e15.physik.tu-muenchen.de Physik Department E15 Technical University Munich 85747 Garching Germany

Cryogenic X-ray detectors for material analysis As supraconducting X-ray detectors offer both high energy resolution and single photon detection they are a very interesting tool for X-ray fluorescence analysis. The resolving power of semiconductor devices often is not sufficient to identify especially light elements in surface sensitive detection. So far the application of cryogenic detectors suffered from the need of very sophisticated cooling techniques. The development of mechanical coolers in combination with demagnetization techniques however allows to reach the mK-temperature range very easily. Both the cooler and some analysis results are presented.

6) Bolometer matrix for X-Ray detection in Astronomy (15mn)

Claude Pigot pigot@asca.saclay.cea.fr CE-Saclay, DAPNIA/SPP, F-91191 Gif sur Yvette Cedex, France.

Presentation of new missions in X-ray astrophysics, requirements on X ray instruments and present state of development of bolometer matrices.