Thanks to high-tech development work and some creative tuning and tweaking, the $650 million Thomas Jefferson National Accelerator Facility in Newport News, Va., can now accelerate beams of electrons to 6 billion electron volts — more energy by half than taxpayers originally paid for. With higher-energy electron beams, researchers using this U.S. Department of Energy laboratory can probe deeper than ever into the atom's nucleus to learn how matter itself is put together.
"No one can foretell the practical results that could come from this research," says Dr. Hermann A. Grunder, director of the Jefferson Lab, as it's called for short. "But history shows a clear pattern. Fundamental knowledge of matter itself has led to useful technologies, from medical X-rays and MRIs to transistors and integrated circuits."
Every atom has a nucleus at its core. These nuclei contain protons and neutrons. Three decades ago, experiments at another electron-accelerator laboratory proved that protons and neutrons contain still smaller bits of matter called quarks. Jefferson Lab was designed to establish exactly how these quarks make up nuclear matter.
This research requires the huge machine at Jefferson Lab's heart: a 7/8-mile-circumference electron accelerator based on advanced superconducting technology. That's where the achievement of the 150% boost in electron-beam energy took place.
This computer-controlled array of hardware and electronics "accelerates" beams of electrons to high energy and then sends them into three gymnasium-sized experiment buildings. There the beams interact with nuclei in small, specially configured experiment targets. House-sized electronics equipment records the results — typically a half-million megabytes of data per day.
To build and commission the accelerator in the late 1980s and early 1990s, Jefferson Lab pioneered the large-scale use of superconducting electron-accelerating technology. It's a delicate, difficult way to accelerate nucleus-probing electron beams. But it slashes operating costs and boosts research productivity. And as a young technology still being developed, it can yield performance advances to those who work hard to improve it.
By the mid-1990s, Jefferson Lab experiments were under way at 4 billion electron volts, just as had been planned. By 2000, scientists, engineers and technicians had become better and better at operating the accelerator, and they had improved both its hardware and software. So during the first weekend in August, the accelerator briefly reached 6 billion electron volts — 150% of the original specification.
This achievement highlights the potential of the superconducting accelerating technology that Jefferson Lab pioneered and is now advancing. Four examples show how awareness of this potential has begun to spread in the high-tech world:
- This fall, the nation's Nuclear Science Advisory Committee will consider a proposal to double the Jefferson Lab energy from 6 to 12 billion electron volts. This energy upgrade would require adding and replacing some accelerator hardware. The laboratory's users — researchers from universities across the country — want the upgrade because it will give them even sharper views into nuclei.
- Under a $70 million contract, Jefferson Lab is providing superconducting accelerating technology for a new research facility being built at Tennessee's Oak Ridge National Laboratory. This Spallation Neutron Source will advance the science, engineering and overall development of space-age materials.
- A national committee of experts last year recommended superconducting technology for a national accelerator project under consideration, the envisioned Rare-Isotope Accelerator (RIA) facility. RIA would advance the study of matter itself through investigations of exotic nuclei like those in stars.
- Jefferson Lab itself is leveraging its superconducting electron-accelerating technology to develop powerful, versatile free-electron lasers, or FELs. Unlike most conventional lasers, an FEL lets operators dial up a specific color of laser light. Selectable color represents an enormous advantage for basic research and an enormous potential for laser-based materials processing, product manufacturing and national defense. Already, Jefferson Lab's initial FEL delivers laser light at over 150 times the power of previous FELs.
The 47-university Southeastern Universities Research Association operates Jefferson Lab for the Department of Energy. The Thomas Jefferson National Accelerator Facility is named after the U.S. president and statesman of science who led the early development of American optimism about science, technology and the future.