Electron Accelerator Made a Top Priority

Jefferson Lab scientists are designing an upgrade that would double their electron accelerator's capacity, hoping to probe deeper into the heart of nuclei to explain physical matter.

The upgrade, on the lab's books for seven years, won approval from the international nuclear physics community two weeks ago when a committee of representatives ranked it one of four long-term priorities for physics research.

The gesture doesn't automatically secure Department of Energy funding for the $150 million project, a step still in Congress' hands. But it lends more credence to the Newport News lab's intent to take its already world-leading facility to the next level.

"This makes us beggars with a better position," quipped Christoph W. Leemann, interim director of Thomas Jefferson National Accelerator Facility. "This was a major hurdle to make."

The project would build a fourth experimental hall onto the accelerator, an electron beam in the shape of a racetrack. The halls are workstations booked years in advance by scientists worldwide to study the movement of electrons.

But the highlights of the accelerator's upgrade are its appendages that would boost the energy of electrons from 6 billion electron volts to 12 billion electron volts, flying them around the curves at the speed of light.

The higher the energy, the deeper scientists can explore into protons and neutrons to study quarks, the basic building blocks of matter.

The deeper scientists can explore, the more clearly they'll see how quarks behave, finally proving long-assumed theories or creating never-anticipated ones.

The higher resolution would be similar to studying a firefly at the center of a football stadium. It would allow scientists even to detect the glue that holds quarks together — previously pristine physics territory.

And the more scientists learn about the smallest particle, the more they can understand the biggest phenomena, such as Big Bang and the evolution of the universe.

"Now really is the time to think about physics just beyond our reach with current facilities," said Donald F. Geesaman, director of the physics division at Argonne National Laboratory in Illinois. "We need to try to understand what is the next physics we want to do."

The Long Range Plan Working Group of the Nuclear Science Advisory Committee, of which Geesaman was a member, wholeheartedly placed the accelerator upgrade above seven other funding proposals, including electron ion collider research and a gamma-ray tracking detector, which can track and study several-hundred matter particles flaying from a single electron collision.

Money for the upgrade looks unlikely in fiscal year 2002, for which President Bush's proposed budget doesn't even allot an inflationary increase to the DOE's nuclear physics section.

But Leemann always had his eyes set on fiscal years 2003 and 2004. He hopes to start construction on the accelerator in 2004, and if funding is constant, finish the build-out by 2007 or 2008. Up to 20 percent of the tab will be picked up by foreign contributors, mostly groups that perform experiments at the lab.

"For decades to come, there isn't any competition in the world planned to be able to reach this type of physics," said Allison Lung, a staff scientist in Jefferson Lab's physics division. "We're the only ones."

— Reach Vandana Sinha at vsinha@pilotonline.com or 446-2318.