CDMS II at Soudan



Essay Series

Ingredients of the Universe

Why Dark Matter?

Dark Matter Candidates

The Search for Dark Matter

Frequently Asked Questions

The Science of CDMS

Direct Detection of WIMPs

CDMS II Detectors

Soudan Installation

Physics Goals


CDMS II is currently running at the Soudan Underground Laboratory in northern Minnesota, U.S.A. The experiment resides on the 27th level at a depth of 2341 feet below the surface (2000 meters water equivalent). The depth of the facility reduces the flux of cosmic ray muons by a factor of 105 from surface levels. When combined with the experiment's active muon veto and passive polyethylene shielding, less than one neutron background event (which could be confused with a WIMP) is expected in a year's exposure of CDMS II's full complement of 30 ZIP detectors.

The detectors are encased in a cold enclosure called the "icebox", cooled to less than 50 millikelvin by an Oxford dilution refrigerator. The icebox is encased in layers of passive shielding (lead and polyethylene) and an active scintillator veto.

Last updated April 28, 2007