Overview:
The Cryogenic Dark Matter Search attempts to locate evidence of the elusive dark matter which should be abundant in our universe, yet is difficult to detect. Leading candidates for dark matter are weakly interacting massive particles (WIMPS), which interact only weakly with ordinary matter (thus explaining why they're so hard to detect).
Detection Process:
The detectors inside the CDMS are composed of germanium and silicon crystal disks, which are cooled to very low temperatures. Because of the low temperature, there is little thermal noise caused by the random motion of particles within the crystal disks, making it easier to detect vibrations from particle interactions.
A particle hitting the detector sends a vibration (or phonon) through the crystal lattice. The phonon is detected through transition edge sensors (TES).
Another set of sensors, called field-effect transistor amplifiers (FET amplifier), are used to detect the ionization of the particle
History:
The CDMS experiment began in a lab under Stanford University, where it operated until 2002. This version of the experiment is now referred to as CDMSI.
In 2003, the experiment moved to the Soudan Mine in Minnesota (along with a new collaboration with the University of Minnesota), sometimes referred to as CDMSII. The sensitivity of the current experimental set-up is promoting many physicists to be optimistic that it will find evidence of dark matter, if it is indeed composed of WIMPs.
Possible Evidence:
On Dec. 17, 2009, the CDMSII announced that it had detected two pulses which were possible WIMP candidates (one on August 8 and the other on October 27, 2007). The low number of events leaves things in doubt, though, and the experimenters themselves estimate that there's a 25% chance that the pulses were caused by background radiation, such as those from neutrino collision. Experiments are continuing in an attempt to detect more such pulses, so that it can be determined exactly what their source is.
