Astropart.Phys.23:325-339,2005 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 CaWO4 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 +- 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.
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 CaWO4 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 +- 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.
The EDELWEISS collaboration is searching for WIMP dark matter using natural Ge cryogenic detectors. The whole data set of the first phase of the experiment contains a fiducial exposure of 4.8 kg.day ...on Ge-73, the naturally present (7.8%), high-spin Ge isotope. The sensitivity of the experiment to the spin-dependent WIMP-nucleon interactions is evaluated using the model-independent framework proposed by Tovey et al.
We present first competitive results on WIMP dark matter using the phonon-light-detection technique. A particularly strong limit for WIMPs with coherent scattering results from selecting a region of ...the phonon-light plane corresponding to tungsten recoils. The observed count rate in the neutron band is compatible with the rate expected from neutron background. CRESST is presently being upgraded with a 66 channel SQUID readout system, a neutron shield and a muon veto system. This results in a significant improvement in sensitivity.
The natural alpha decay of 180W has been unambiguously detected for the first time. The alpha peak is found in a (gamma,beta and neutron)-free background spectrum. This has been achieved by the ...simultaneous measurement of phonon and light signals with the CRESST cryogenic detectors. A half-life of T1/2 = (1.8 +- 0.2) x 10^18 y and an energy release of Q = (2516.4 +- 1.1 (stat.) +- 1.2 (sys.)) keV have been measured. New limits are also set on the half-lives of the other naturally occurring tungsten isotopes.
