Get Ready to Go Underground at Jefferson Lab’s 2024 Open House

  • 2018 Open House accelerator tunnel

The accelerator tunnel tour in Jefferson Lab's 2018 open house event.

For the first time, two distinct sections of the particle accelerator tunnel will be open to the public at the long-awaited science showcase

NEWPORT NEWS, VA – For as long as the U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility has opened its gates to the public for its Open House event, the primary particle accelerator has been the must-see exhibit.

Each time, the Continuous Electron Beam Accelerator Facility, or CEBAF, acts as a beacon of scientific discovery drawing thousands of curious minds. It’s not often people get to go behind the fences at Jefferson Lab, much less get up close to one of the world’s most powerful microscopes for studying the atom’s nucleus.

Nestled beneath about 25 feet of earth, CEBAF is a 7/8-mile, racetrack-shaped circuit that is the cornerstone of the nuclear physics research conducted at Jefferson Lab. It uses a highly focused beam of electrons that zip through metal tubes at nearly the speed of light before smacking into an array of atomic targets.

For years, those attending a Jefferson Lab Open House could tour one or both of the straight sections of the tunnel, called linacs. But this year, on June 8, guests can see more of the accelerator than ever. Jefferson Lab will open not just CEBAF’s straight sections, but also its curves – known as arcs.

“We have opened up the linacs before, but never the arcs,” said Paul Vasilauskis, the Accelerator Operations Group Leader who manages the crew chiefs and operators who run the research machine. “This is new for us.”

The arcs contain stacked rows of powerful magnets and instruments that steer the electron beam from one linac to the other. Numbering roughly 2,200 and coming in about 50 varieties, the magnets range in size from a few cubic inches to several yards. Some can weigh as much as 5 tons.

The linacs are driven by superconducting radiofrequency (SRF) cavities, housed within 6-ton, 27-foot-long cryomodules that propel electrons to extraordinary energies.

“The tunnel will be cool to see,” Vasilauskis said. “There is all of this neat, shiny hardware and instrumentation – big things that people will find fascinating.”

Beyond the wow factor, there’s a lot to learn.

Visitors can expect to spend about 20 minutes on the self-guided walking tour of the accelerator tunnel. After descending four flights of stairs, they will be greeted by Jefferson Lab engineers and technicians at the South Linac and East Arc. The staff volunteers will provide some “did-you-knows” and insights into the science behind CEBAF, including how it is safely operated and maintained while furthering our understanding of the universe.

But keep in mind, temperatures inside the subterranean passage can climb as high as 90° on a hot June day, so remember to hydrate and dress accordingly. The only access available for the accelerator tours entails navigating down and then up four flights of stairs, so visitors are encouraged to consider this limitation in planning their visit.  Two of three experimental halls, which also require descending underground, are available for wheelchair access, and all three of the experimental halls will offer golf cart rides into those areas for those who have difficulty navigating stairs or steep ramps.

Vasilauskis has participated in eight open houses since joining Jefferson Lab in 2001. He still enjoys the Herculean effort of preparing the site for the highly anticipated event and appreciates working with his teammates – some of whom have never experienced the daylong science showcase.

“There is always so much excitement at the lab around the Open House, and I understand why,” he said. “For some of us, this might be the only chance to show our friends and loved ones what goes on here.”

For the latest on the Jefferson Lab’s 2024 Open House, visit the event website or the Facebook event page.

To be added to our event information distribution list for information updates and event reminders, email.

Contact: Duane Bourne, Jefferson Lab Communications Office,


Jefferson Science Associates, LLC, manages and operates the Thomas Jefferson National Accelerator Facility, or Jefferson Lab, for the U.S. Department of Energy's Office of Science. JSA is a wholly owned subsidiary of the Southeastern Universities Research Association, Inc. (SURA).

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