CRESST - Cryogenic Rare Event Search with Superconducting Thermometers
Weakly interacting massive particles (WIMPs) are well motivated candidates to account for most of the non-baryonic cold dark matter in the universe.
The CRESST experiment located in the Gran Sasso Underground Laboratory in Italy aims at the direct detection of WIMPs by means of cryogenic detectors, operated at a few mK. CaWO4 crystals (~300g) are used as target material.
The detection mechanism is as follows: an incident particle (e.g. a WIMP) scatters off nuclei in the target crystal, leading to a phonon signal and with a small fraction of the deposited energy to scintillation-light. The scintillation-light is detected by a separate light detector equipped with a TES (transition edge sensor), the phonon signal is detected by a TES on top of the CaWO4 crystal. The TESs are based on superconducting tungsten thin films (Tc ~ 10mK). The detection of both the phonon and the scintillation light signal allows to efficiently reduce the background originating from gamma and beta events.
Presently, the experiment is in an upgrade phase to gain sensitivity for the WIMP nuclear scattering cross section of up to 10−8 pb. To achieve this sensitivity within a resonable time scale, about 10kg of target material are required.
Currently the CRESST collaboration is commissioning a new detector installation. The upgraded setup allows the operation of up to 33 detector modules. Data taking has commenced in October 2006.
The experiment is performed by a collaboration of:
Our main contribution to the experiment right now is connected to the detector production (i.e. thin film and CaWO4 single crystal production), improving detector performance and calibration of the detectors to nuclear recoils via a Maier-Leibnitz-Labor in Garching.which is presently being set up at the
For more details concerning CRESST please take a look at the CRESST web site.