Va. laboratory begins study of nature of matter Electron accelerator took 20 years, cost $600 million


NEWPORT NEWS, Va. -- After years of planning and construction, and months of tests and delays, the first experiment at the Continuous Electron Beam Accelerator Facility has finally begun.

The six-week project, which began this week, marks a milestone in the 20-year development of the $600 million Newport News physics lab, where researchers are studying the fundamental nature of matter -- especially subatomic particles at the core of atoms, the building blocks of matter.

The Department of Energy has pinned much of its hopes for future research on CEBAF, in the wake of Congress' decision in 1993 to scrap the ambitious Superconducting Super Collider project in Texas.

The experiment's start was delayed throughout summer and fall as CEBAF physicists struggled to produce an electron beam that was both accurate and continuous -- a requirement to obtain usable data.

By Christmas, about 100 experimenters -- most from university groups -- will have had a hand in the collection of data from 7 million particle collisions caused as the electron beam strikes targets.

CEBAF experiments, like those at other national laboratories, are geared toward a far-reaching understanding of the subatomic world akin to the peek into the distant regions of the universe that the Hubble Space Telescope is giving astronomers.

To take this journey into the infinitesimally tiny world of the atom, CEBAF uses a continuous stream of electrons that jets around an underground oval through supercooled cavities at close to the speed of light.

The beam, which generates 4 billion electron volts of energy during its 4.37-mile journey, then strikes its target. The targets are ultra-thin sheets of carbon, iron or gold foil, chosen because they won't melt, said Roger Carlini, physicist and leader of Hall C, the underground cavity where the first experiment is taking place.

As electrons collide with the target's protons, highly sensitive spectrometers in one of CEBAF's three halls -- two are being completed -- record the speed, mass, energy and direction of the particle collisions.

From this data physicists can tell if a particle is or has become electrically charged. Although the collisions cannot be seen because they are too small, physicists can deduce what has taken place.

It may be months or years, physicists say, before conclusions can be drawn about the data being collected at CEBAF. But while they note that it's premature to speculate on any practical applications for the research, they remain confident that some good will come of it.

"Ninety percent of the time, you get nothing," Dr. Carlini said. "But 10 percent of the time, you get how we made our modern world."

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