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Show Physicists report on Cosmic Ray Wind med. "Previous experiments that failed to detact a 'wind' have been either imprecise or inaccurate. Most measured low energy particles that had been pulled off course by the magnetic field of the sun before they hit the earth "Our measurments are much more precise. The 500-foot 500-foot layer of rock above our detectors shields them from the rain of low energy rays and allows only the most energetic and directionally true rays to the monitored," he said. Most of the particles detected in the Mayflower Mine have an energy slightly above a trillion electron volts. Other experimenters have worked at energies only one-fourth that high. The underground detector is in a 100-ton concrete block array about five feet wide by five feet high running for a length of 100 feet through the mine tunnel. It consists of 300 plastic "counters" shaped like paddles and protected by metal sheets. Electric pulses produced by cosmic rays going through the counters are monitored by a computer, also housed in the tunnel. The automated system operates around the clock, and technicians need to be present only to change tapes every two weeks. Groom says results from the Mayflower Mine fit in with results obtained recently from high energy cosmic ray experiments in Hungary, Japan and Tasmania. "We plan to take data for another three years to reduce the error range in our data and extricate confusion in thegdata due to the closeness of the solar and stellar days," Groom says. Results of the first year's findings are to be submitted for publication in a scientific journal soon. "Utah has become one of the world centers for cosmic ray research because of two decades of support by the National Science Foundation," Foun-dation," Groom says. Mayflower is the second underground observatory built by Utah researchers with NSF funds. The first was a neutrino detector located in the Silver King Mine in Park City which provoked international interest in the use of cosmic rays as a tool for studying , ultra-high-energy collisions. NSF is currently supporting sup-porting a second unique cosmic ray observatory at the U. This is "Fly's Eye", an array of giant mirrors which this winter began tracking the scintillating light of cosmic ray showers as they descend through the night sky. Fly's Eye is located on a hill at the U.S. Army's Dugway Proving Ground 80 miles west of Salt Lake City. University of Utah physicists announced Friday preliminary findings that support the widely accepted but unproven theory that a "gentle wind" of cosmic rays is streaming along the spiral arms of the earth's galaxy. The data comes from the first year of operation of a unique observatory half a mile inside the old Mayflower Mine near Park City, Utah. The tentative results were announced by graduate student Dan Cutler at a meeting of the Utah Academy of Science, Arts and Letters in Cedar City. Dr. Donald Groom, associate professor, and Dr. Haven E. Gergeson, professor, are directing the research. Dr. John Davis of Los Alamos Scientific Laboratory is collaborating on the project. "Our data gives evidence of a 'wind' blowing at about 100 kilometers per second through the galaxy." says Groom. "That is a tiny velocity to measure in astronomical terms. It compares to the 30 kilometers per second at which the earth is moving about the sun. We spent three years building the equipment that would perform this delicate experiment." ex-periment." The underground experiment ex-periment . was designed four years ago to take the most precise measurements ever make on the velocity of the suspected cosmic ray drift and the theory that the stream is wafting slowly into space through an unknown "exit hole" in the galaxy. "The basic paradox of this widely accepted theory is that scientists have never been able to find this 'wind' and the rays seem to be trapped within the galaxy," Groom says. "But evidence from other experiments shows that the rays are very young on a galactic time scale, only two million years old. They appear much too young to have been trapped since the galaxy was' for- |