ITHACA, N.Y. -- The Cornell High Energy Synchrotron Source (CHESS), one of the world's leading centers for X-ray research in biology and materials science, is building a major addition that will provide a quantum leap in its capabilities.
Although CHESS is largely funded by the National Science Foundation (NSF) as a National Research Facility, the addition is being funded entirely by $3 million from the Cornell University administration. An NSF grant of $2.5 million over three years will fund the X-ray beam line equipment for the building. Cornell also is funding two graduate fellowships for students who will work in the new facility.
"These are substantial commitments by the university and the NSF for faculty research," says Sol Gruner, director of CHESS. "There has been a tremendous amount of university support from the beginning."
CHESS is a 19-year-old facility housed in Wilson Laboratory on the Cornell campus. Wilson also houses the Cornell Laboratory for Nuclear Studies (LNS), which operates the Cornell Electron Storage Ring (CESR), the provider of X-rays for CHESS.
Due to its national facility status, CHESS is open to all researchers on a competitive basis. Currently it supports 600 to 700 user visits a year, and requests for beam time exceed supply by about a factor of three, according to Associate Director Donald Bilderback. Only about 25 percent of users are from Cornell, and it is not unusual for faculty to be denied research time.
But because the new facility, dubbed G-Line, will be supported by Cornell faculty research grants, 80 percent of research time will go to Cornell personnel. "We are very excited about this because it will go a long way toward meeting Cornell's rapidly growing demand for more X-ray beam time," says Gruner.
At the five existing CHESS high-energy X-ray beam lines, multifaceted research and development is carried out in nine lead-shielded experimental stations. The new facility will produce X-rays at intensity levels of about five to 50 times greater than the five other lines, making it among the world's most intense.
CESR, the underground laboratory that provides CHESS's X-rays of up to 100 kilovolts (100,000 volts), is among the world's most powerful rings for X-ray production and is operated primarily for high-energy physics experiments. A half-mile in circumference, it stores counter-rotating particle beams traveling at nearly the speed of light. Physicists in Wilson Lab study subatomic particles created in the collisions of the beams. A by-product of the beams is copious amounts of X-rays that escape through beryllium windows located at specific locations in the storage ring and are fed into experimental stations, or hutches, for use by CHESS researchers.
Work on the new facility began in May, when CESR closed for a rare, four-monthlong, major upgrade. The last such closing was in 1995. In just four months, the synchrotron tunnel, located nearly 50 feet below Alumni Field on the Cornell campus, has to be unearthed and much of the new building next to the tunnel constructed. The earth then has to be carefully replaced, making sure it is loaded equally on all sides of the storage ring. "The storage ring is sensitive to a fraction of a millimeter of motion, which puts great constraints on the engineers," says David Rice, deputy director of accelerator physics at LNS. "It's going to be a difficult construction job."
Complicating the project, the 3,000-square-foot facility is being built into the side of a hill, almost entirely underground, with only a 20-by-60-foot face left exposed. The hill has to be retained so that it doesn't slide down into the excavation. The building will be linked to the Wilson Lab by a 1,000-square-foot underground passageway.
The heavy excavation and installation of the shielding walls and earth must be completed in the four months before CESR is turned back on because the equipment in the tunnel is extremely sensitive to vibration and because of radiation produced by the operating ring. Once the shielding is completed, however, light construction and completion of the new building can continue while CESR is running. Building is expected to be completed by January next year, following which equipment will be installed. Startup of the new facility is expected in summer 2000.
Heat-load testing will be critical because the total X-ray power provided by G-Line will be about 16 kilowatts, comparable to an arc welder, says Joel Brock, associate professor of applied and engineering physics and the lead researcher on the G-Line, together with Gruner, chemistry Professor Hector Abruna, physics Professor Barbara Cooper and Chris Ober, associate professor of materials science and engineering. "These X-ray beams can burn through metal walls very easily," he says. Fortunately, the CHESS staff, which is taking the lead in designing G-line, is the world leader in high-heat load X-ray optics.
Of the three experimental stations on G-Line, says Brock, one will be used for study in such areas as the time-resolved response of large molecules to electric fields, high pressure stimuli and mechanical deformation. The systems to be studied range from liquid crystals used in computer displays to synthetic silk and other biopolymers. Another station will be used for the study of the growth of semiconductor films and will heavily involve faculty and students from the Cornell Center for Materials Research. The third station will be for general purposes.
"What makes this really unique is that it's here on campus," says Gruner. "It's really the only such facility in the U.S. actually embedded in the central campus of a university." As a result, G-Line investigators intend to emphasize the educational aspects of the facility for undergraduate and graduate research. They also expect to run a summer school, a Research Experiences for Undergraduates program and provide K-12 outreach.
Bilderback also sees the G-Line facility as a place to train students to take jobs in other facilities. "The number of rings worldwide continues to increase, so we see ourselves filling a niche area in training people who can run and operate these rings for X-ray purposes," he says.
Related World Wide Web sites: The following sites provide additional information on this news release. Some might not be part of the Cornell University community, and Cornell has no control over their content or availability.
CHESS : http://www.chess.cornell.edu
G-line construction: http://public-database.chess.cornell.edu/G-line/CHESS_G_line_Images.htm
The above post is reprinted from materials provided by Cornell University. Note: Content may be edited for style and length.
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