Jefferson Lab in Newport News has reached a "major milestone" in its drive to double the energy of its electron accelerator and become the only facility in the world capable of answering key questions about quarks, the building blocks of matter.
On April 1, it revved up its new and improved Continuous Electron Beam Accelerator Facility (CEBAF) in a test run to deliver the highest-energy electron beam the lab has ever produced. In a couple of weeks, it will far surpass even that.
"This achievement is a major milestone in the commissioning of the upgraded CEBAF," said lab director Hugh Montgomery. "Although it's early yet as far as delivering beam for experiments, we are beginning to see the flowers that will become the fruits of our labors from this upgrade."
The CEBAF accelerator at Jefferson Lab, officially the Thomas Jefferson National Accelerator Facility, has allowed scientists from around the world to conduct fundamental science since 1995.
The accelerator shoots electrons at ultra-high speeds around a huge underground "racetrack" to hit targets in one of four experimental labs, or halls. As electrons collide with neutrons and protons in those targets, the collision allows scientists to study their basic quark structure.
Until now, the maximum energy the machine could reach to accelerate electrons was just under 6 GeV, or 6 billion electron volts. In 2008, the lab began a $338 million renovation and construction project that includes doubling the energy of the CEBAF to 12 GeV. In late 2012, it had to shut down the accelerator to complete that upgrade.
Doubling the CEBAF's energy will significantly enhance the science, explained Allison Lung, deputy project manager for the 12 GeV Project Office.
"If you think of the accelerator like a microscope," Lung said, "if I can increase the energy that the electrons have, I get a much better and deeper resolution."
The April 1 runs delivered 6.1 GeV — more energy than the CEBAF ever before produced, and one of several milestones the lab must hit under U.S. Department of Energy specifications as it works to reach full capacity.
While 6.1 GeV may not sound like a marked leap on the way to 12 GeV, Lung said it's a remarkable feat.
"The complexity of this kind of an accelerator," she said, "where we have touched and or replaced virtually every one of the thousands and thousands of components in that machine in order to install the new 12 GeV machine, the fact that we were able to advance this far in the commissioning of the machine and produce more than what it was ever capable of doing before is a key milestone."
And in just a couple of weeks, Lung said, they expect the CEBAF to deliver a beam greater than 10 GeV.
When the CEBAF upgrade is finally complete, it will offer a research capability that's not only new to Jefferson Lab, she said, but one that is "unique in the world."
While there are machines that can accelerate different particles at much higher energies than 12 GeV, she said, theirs is the only machine using electrons, with its particular polarization and current.
And it will allow scientists to explore in greater detail the question of why you never see one quark by itself, Lung said, but confined in pairs or groups.
Such science, she said, focuses on the most fundamental mysteries of human existence: "Why are we here? Why, when I sit down in a chair, don't I fall through to the floor? Why is it that that particular combination of quarks and forces takes on that material property, while a different combination of quarks and forces makes up the human body?"
The lab expects to have two of its halls back in operation for physics in 2015, including the newest, Hall D, which was built during the renovation and will be the only one receiving the 12 GeV beam.
The other two halls are expected to be ready for research again in 2017, Lung said, but Halls A, B and C will receive beams of up to 11 GeV.
Jefferson Lab is managed and operated by Jefferson Science Associates for the DoE's Office of Science. Jefferson Science Associates is a joint venture of the Southeastern Universities Research Association and PAE Applied Technologies.
Dietrich can be reached by phone at 757-247-7892.