What is the CDMSII experiment?

In a nutshell, the experiment seeks to catch the extremely unsociable WIMPs interacting with matter--specifically, the nuclei of germanium or silicon atoms. The germanium and silicon detectors, which resemble hockey pucks, are stacked inside a detection chamber 2,341 feet below the surface of the Earth. The Earth's crust filters out cosmic rays and other stray particles. An interaction between a WIMP and a germanium or silicon atom would produce a movement of electric charge and the generation of heat, but so little of both that the detection chamber must be cooled to a tenth of a degree above absolute zero to cut out background noise. But neutrons generated underground could pass through the apparatus and produce a signal similar to that expected for a WIMP. The first data, however, show no neutrons sneaking through, meaning the background is low enough to give the experiment a very good shot at detecting the real mccoy.


Believe it or not, this is one of the most common questions asked to dark matter physicists. A common answer is that understanding the form dark matter takes will allow us to confirm or contradict current Big Bang nucleosynthesis models. Other researchers may cite the fact that dark matter's gravitational effects distort much of our astronomical data, thus we must understand dark matter's dorm in order to correctly interpret data. BUT...what it all boils down to in the end is that dark matter is another mystery in our universe that has yet to be solved. It is an exciting question that physicists and amateur astronomers alike find fascinating and worth exploring!

What is a physics experiment doing in a mine?

The CDMS II project is currently underway 1/2 mile below ground in the Soudan Mine in northern Minnesota (right). Our germanium and silicon detectors are searching for WIMPs (Weakly Interacting Massive Particles): a dark matter candidate. WIMPs don't like to be seen (weakly interacting), so detecting and counting them requires near 'perfect' conditions! BUT, the earth is constantly bombarded with other particles from the universe: muons & cosmic rays, and these extra particles resemble WIMP's to our detectors. By placing everything deep underground, we use the earth itself as a shield from this unwanted 'noise' of extra particles. In this way we are able to filter the some of the particles entering our detector so that when a WIMP is detected, we can be sure it is one.

Click on the link below to find out more about CDMS II!

CDMS Education Poster
download a color PowerPoint poster

CDMS II Overview