Main Injector Neutrino Oscillation Search (MINOS)

The Main Injector Neutrino Oscillation Search, or MINOS Experiment, located half a mile underground in the historic Soudan Iron Mine in northeastern Minnesota, will probe the secrets of subatomic particles called neutrinos. The neutrinos will be produced by a particle accelerator at Fermi National Accelerator Laboratorynear Chicago. Beginning in February 2005, neutrinos in the NuMI (Neutrinos at the Main Injector) beam will be directed 450 miles straight through the earth, from Fermilab to Soudan--no tunnel needed.

In Minnesota, a 6,000-ton steel detector will search for neutrinos that have changed from one kind to another during the split-second trip. More than a trillion man-made neutrinos will pass through the MINOS detector each year. Because neutrinos interact so rarely, only about 1,500 of them each year will collide with atoms inside the detector. The rest will pass through with no effect. The 200-plus experimenterswill use the change from one type of neutrino to another as the key to unlocking neutrinos' secrets: Where do they come from, what are their masses and how do they change from one kind to another? How are neutrinos related to the mysterious dark matter that makes up almost a quarter of our universe?