U-M scientists to help build world's largest particle accelerator

By Sally Pobojewski
News and Information Services

Seven years from now when the world's most powerful particle accelerator begins smashing protons together in an underground tunnel near Geneva, Switzerland, scientists will be able to "see" the collisions thanks to a sensitive particle detector built in p art by U-M physicists.

Officials from Europe and the United States signed an agreement Dec. 8 to help fund the Large Hadron Collider (LHC)---a 16-mile-circumference particle accelerator under construction at the European Laboratory for Particle Physics (CERN). Two international scientific teams will design and build two massive particle detectors for use in the LHC. Funding for the project is being provided by the U.S. Department of Energy and the National Science Foundation.

"In 2005, the frontier of high-energy physics most likely will be in Geneva," says physics Prof. Homer A. Neal, who is directing U-M involvement in the project. "Since U-M faculty helped plan and design experiments for the Superconducting Supercollider before the project was cancelled, it's only natural that we would be involved in the European Supercollider."

Neal and six members of the Department of Physics, along with hundreds of other scientists worldwide, will be part of the ATLAS collaboration. ATLAS and CMS are the two major particle detectors that will be installed inside the Large Hadron Collider at CERN.

According to Neal, scientists from the U-M and six other universities will design and build key components called the muon spectrometer drift chambers. "These drift chambers are 18-foot-long aluminum tubes about one-inch in diameter," Neal explains. "A n extremely thin gold-plated, high-voltage wire runs down the center of each tube. The tubes are used to detect the location of charged particles produced when two protons collide inside the LHC. About 500,000 individual drift chambers will be needed fo r ATLAS and a significant fraction of these will be built here in Ann Arbor.

"During the ATLAS experiment, thousands of computers will monitor the time it takes for charged particles to drift to the center wire," Neal explains. "Scientists will use this information to determine exactly where each particle passed through the drif t chamber array. Combining the data with that from other subsystems in the experiment will permit us to study what really happens when the basic particles of nature collide."

Neal says U-M faculty expect to involve many graduate and undergraduate students in the ATLAS project, both to help build drift chambers and to assist with running the experiment in Geneva. Neal and Steven Reucroft, a researcher in the CMS collaboration , have a pending grant proposal with the National Science Foundation that would enable undergraduates to spend summers in Geneva working on LHC projects. Joseph Kuah, a senior majoring in physics and engineering, spent the summer of 1997 in Geneva workin g with Neal.

A second group of faculty from the School of Information may use the U-M ATLAS effort as a testbed to study issues related to worldwide computer networking, on-line scientific collaborative research and high-speed data communications. "The ATLAS experim ent will generate approximately 100 times more data than has been generated by any previous data-intensive study ever undertaken in any field, including NASA projects," Neal adds. "The challenges will be awesome."

Other U-M physicists who are members of the ATLAS detector team include Norman Amos, assistant research scientist; Robert C. Ball, senior engineering research associate; Myron K. Campbell, associate professor of physics; J. Wehrley Chapman, professor of physics; Jianming Qian, assistant professor o f physics; Gregory Tarle, professor of physics; and Andrew D. Tomasch, assistant research scientist.