The currently most performing detectors for the search of non-baryonic Dark Matter, and in particular of the neutralino, predicted by supersymmetric models, are germanium and silicon-based detectors like Edelweiss and CDMS. While achieving nowadays sufficiently high sensitivities for testing the most optimistic supersymmetric models, these detectors are mainly sensitive to the spin-independent interaction channel with the neutralino.
Superfluid 3He-B at ultra-low temperatures is an appealing target material for bolometric particle detection, and particularly for the search for non-baryonic Dark Matter. The main arguments in favour of 3He are its non-zero nuclear magnetic moment (allowing therefore to explore the spin-dependent interaction channel) combined to the extremely high sensitivity of superfluid 3He bolometers and the possibility of efficient neutron background discrimination.
ULTIMA is a new ANR project of a large detector on a basis of superfluid 3He at ultra-low temperatures (100 microKelvins) for the search for non-baryonic Dark Matter. We review recent advances of the application of superfluid 3He for bolometric particle detection, using Vibrating Wire Resonators for thermometry. A multicell prototype of 3 adjacent bolometers has been developed to allow for background event discrimination by simultaneous detection in different cells. One of the cells contained a low activity 57Co source producing electrons mainly at about 7 and 14 keV, in order to demonstrate the possibility to detect low energy events. We review different tests of the current detector prototype, by thermal neutrons, cosmic muons and low energy electrons. Future directions of the detector project will be discussed.
CRTBT, CNRS, Grenoble, France (collaboration avec Eddy Collins, Henri Godfrin)