CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) is a dark matter search experiment involving the Max-Planck-Institut für Physik in Munich, the University of Oxford , the Technische Universität München, the Eberhard Karls Univeristät in Tübingen and the Laboratori Nazionali del Gran Sasso. The experiment searches for the elastic scattering of dark matter particles off atomic nuclei, using cryogenic detectors, operating at 10–15mK temperature. A particle collision inside a detector creates a large number of phonons inside an absorber crystal, these thermalise inside a superconducting thermometer on the surface of the crystal. As the thermometer is biased in centre of its superconducting transition, this small increase in temperature, produces a relatively large change in resistance, which is then read out. To reduce the background rate the experiment is located in hall A of the underground Laboratori Nazionali del Gran Sasso (LNGS). CRESST phase I ran until 2001 using 262g sapphire detectors. The experiment was then upgraded to CRESST II using a new design of cryogenic phonon scintillation detector.

The CRESST II detector modules use 300g scintillating absorber crystals (CaWO₄ or ZnWO₄). In addition to the thermometer on the crystal surface, an additional cryogenic scintillation light detector measures the scintillation light produce by an interaction. The module is enclosed in a reflective housing. By comparing these two signals, we can distinguish electron recoil events (which provide more scintillation light) from nuclear recoils. As WIMPs are expected to scatter off nuclei, we can reject the background from α, β, and γ events which cause electron recoils. To avoid the remaining background from neutrons, we have installed a polyethylene shield.

The experiment is now running with this improved setup. The results of a preliminary commissioning run have allowed us to set a limit on the WIMP scattering cross-section of 4.8×10^-7pb.

The main contributions of the Oxford group towards the experiment have been developing the data analysis software; investigating scintillation materials; and developing the 66-channel SQUID readout.