We present first significant limits on WIMP dark matter by the phonon-light technique , where combined phonon and light signals from a scintillating cryogenic detector are used .
Data from early 2004 with two 300 g CRESST-II prototype detector modules are presented , with a net exposure of 20.5 kg days .
The modules consist of a CaWO _ { 4 } scintillating “ target ” crystal and a smaller cryogenic light detector .
The combination of phonon and light signals leads to a strong suppression of non-nuclear recoil backgrounds .
Using this information to define an acceptance region for nuclear recoils we have 16 events from the two modules , corresponding to a rate for nuclear recoils between 12 and 40 keV of ( 0.87 \pm 0.22 ) events/ ( kg day ) .
This is compatible with the rate expected from neutron background , and most of these events lie in the region of the phonon-light plane anticipated for neutron-induced recoils .
A particularly strong limit for WIMPs with coherent scattering results from selecting a region of the phonon-light plane corresponding to tungsten recoils , where the best module shows zero events .