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CDMS research group at the University of Zurich |
The CDMS experiment operates 5 towers with a total of 30 Ge and Si detectors at the Soudan Mine in Northern Minnesota. Run123 (October 2006 to March 2007) has yielded a raw exposure of 430 kg day in Ge, and Run124 is ongoing since April 2007. The expected total raw exposure in spring 2008 is larger than 1300 kg day in Ge, corresponding to an estimated sensitivity to spin-independent WIMP-nucleon cross sections of about 2x10-8pb (2x10-44cm2). The picture shows the 5 towers in their cold volume (icebox), viewed from the top.  The latest published CDMS results were obtained from operating 12 Ge and Si detectors at a temperature of about 20 mK at the Soudan Mine in 2004. No dark matter signal exceeding the expected background had been detected. The probed WIMP-nucleon cross section for spin-independent interactions goes down to 1.6x10-43cm2 for a WIMP mass of 60 GeV/c2. The figure below shows experimental results and theoretical predictions for the WIMP-nucleon cross section as a function of the WIMP mass. The new CDMS limit is displayed as a solid red line. The parameter space above the red curve is excluded. The filled yellow and grey regions show the parameter space for neutralino dark matter predicted by various supersymmetric models.  Our group is mainly involved in data analysis, in Monte Carlo simulations of the expected gamma, beta and neutron backgrounds from the radioactivity of the detector materials and shields, in WIMP analysis for alternative dark matter candidates such as Kaluza-Klein dark matter and SIMPzillas, and in the operation of the experiment at the Soudan Laboratory. We are currently leading the collaboration wide Backgrounds Working Group. CDMS in the news: Nature Slashdot BBC Science UF PR |