Jefferson Lab accelerator upgrade completed: Initial operations set to begin while experimental equipment upgrades continue


Aerial of Jefferson Lab

NEWPORT NEWS, VA. – The Department of Energy's Thomas Jefferson National Accelerator Facility (“Jefferson Lab”) has just received formal approval from DOE to begin initial operations of the Continuous Electron Beam Accelerator Facility (CEBAF) as part of its ongoing $338 million upgrade.

With the approval of Critical Decision-4A, Accelerator Project Completion and Start of Operations, by DOE, Jefferson Lab staff can continue development activities to bring the accelerator up to its full capabilities, while also continuing to install upgraded instrumentation in two of the existing three experimental halls and implement new instrumentation in its newest experimental hall. This very important milestone marks the completion of the accelerator and civil portions of the 12 GeV CEBAF Upgrade project necessary to mark the transition to initial operations of the facility. Once fully completed, the newly upgraded CEBAF will become an unprecedented tool for the study of the basic building blocks of the visible universe.

"My sincere congratulations to the entire team on reaching this very important milestone in the project in such fine fashion. It is a tribute to the dedication, skill, and knowledge of everyone--from the people on the line, to the accelerator staff, the project management team, the scientists, and laboratory management. Outstanding!" said Dr. Tim Hallman, Associate Director of Science for Nuclear Physics in DOE’s Office of Science.

The CEBAF accelerator, an Office of Science User Facility, produces a stream of charged electrons that scientists use to probe the nucleus of the atom, its protons and neutrons, and their quarks and gluons. CEBAF delivered 6 GeV electrons (electrons with 6 billion electron-volts in energy) in its original configuration. Construction began in 2008 for the 12 GeV Upgrade to double CEBAF's maximum operational energy and includes the construction of the fourth experimental hall, as well as upgrades to equipment in the existing halls.

Following completion of the CEBAF accelerator upgrade tasks this spring, the machine achieved several critical commissioning milestones that qualified it for consideration of this next approval step. The accelerator has been in a scheduled maintenance period since May 11. Now, with the approval of Critical Decision-4A, Jefferson Lab staff and visiting scientists may continue commissioning the accelerator and dependent upon funding availability, some limited early physics running may be feasible as the capabilities of the machine are ramped up and instrumentation is implemented.

"This approval comes five months ahead of schedule, a testament to the diligent efforts of everyone involved with the project," said Hugh Montgomery, Jefferson Lab director.

As Jefferson Lab performs beam development activities to bring the accelerator up to its full capabilities, the project continues to work toward CD-4B, Approve Experimental Equipment Project Completion, which is scheduled for September 2017. 

"I sincerely hope everyone can take a few moments to look up from their toils and savor this important accomplishment – right before wiping their brow, taking a big breath, and continuing with renewed spirit and vigor to achieve the grand success of CD-4B," Hallman said. "Our journey continues, but this is a really nice scenic overlook we have reached along the way."

Jefferson Lab is a world-leading nuclear physics research laboratory devoted to the study of the building blocks of matter inside the atom's nucleus – quarks and gluons – that make up 99 percent of the mass of our visible universe. The upgrade will enable further study of the properties of these building blocks, how they are formed, how they interact, and the forces that regulate these interactions.


Contact: Kandice Carter, Jefferson Lab Public Affairs, 757-269-7263,


Jefferson Science Associates, LLC, a joint venture of the Southeastern Universities Research Association, Inc. and PAE Applied Technologies, manages and operates the Thomas Jefferson National Accelerator Facility, or Jefferson Lab, for the U.S. Department of Energy's Office of Science.DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, visit