Livermore Lab Collaboration Seeking Nature Of Neutrinos

Joining an international team of scientists, Livermore researchers will use the MINOS detector, located deep in a historic iron mine in northern Minnesota, to explore the nature and properties of neutrinos. After four years of mining and construction, workers finished building the first of two detectors for the MINOS particle physics experiment.

Scientists have discovered three different types of neutrinos: electron, muon and tau. All three are hard to detect, but play an important role in processes such as radioactive decay and supernovae, the cataclysmic death of massive stars. They are also unleashed in nuclear reactors and in the detonation of nuclear weapons.

Another detector for the MINOS experiment, smaller in size than the one up and running in the Minnesota mine, will be built at Fermi National Accelerator Laboratory in Batavia, Ill., and is scheduled for completion next year.

The operating detector is currently recording cosmic ray showers penetrating the earth. The data will provide the first tests of matter-antimatter symmetry in neutrino processes.

Though neutrinos are one of the most pervasive forms of matter in the universe, they are difficult to detect. In early 2005, Livermore scientists will use the Fermilab beam line to measure the properties of neutrinos. The detector will catch the neutrinos created at Fermilab's Main Injector accelerator, which sits 450 miles away from the Soudan, Minn. mine. It will allow scientists to directly study the oscillation of muon neutrinos into electron neutrinos or tau neutrinos under laboratory conditions.

Using both detectors and the beam line, physicists hope to measure details about the nature of neutrino oscillations. For example, they hope to discover the fraction of a beam that can change from one type to another at a given energy by measuring the fraction of oscillations at each energy. In addition, they hope to determine the oscillation length, which is the distance a beam of neutrinos of a particular energy must travel to transform from one neutrino type to another and back again.

"Creating a beam line of neutrinos is crucial to determine the makeup and properties of these particles," said Peter Barnes, an LLNL physicist who is participating in the MINOS experiment.

In addition to Barnes, Livermore's MINOS team includes: Ed Hartouni and Douglas Wright.

Other MINOS participants include: Argonne National Laboratory; University of Athens; Brookhaven National Laboratory; Caltech; University of Cambridge; College de France; Fermilab; Harvard University; Illinois Institute of Technology; Indiana University; ITEP-Moscow; Lebedev Physical Institute; University College London; Macalester College, Minnesota; University of Minnesota; University of Pittsburgh; IHEP-Protvino; Rutherford Appleton Lab; Soudan Underground Laboratory; University of South Carolina; Stanford University; University of Sussex; Texas A&M University; University of Texas at Austin; Tufts University; UNICAMP-University of Sao Paulo, Brazil; Western Washington University; and University of Wisconsin-Madison.

Founded in 1952, Lawrence Livermore National Laboratory is a national security laboratory, with a mission to ensure national security and apply science and technology to the important issues of our time. Lawrence Livermore National Laboratory is managed by the University of California for the U.S. Department of Energy's National Nuclear Security Administration.