The linear accelerator at SLAC National Accelerator Laboratory in Menlo Park has been shut down after a June 25 fire that damaged an electrical cabinet and its interior equipment that serve the accelerator.
The shut-down has temporarily shut off the source of high-intensity X-rays for the Linac Coherent Light Source (LCLS) and FACET, the Facility for Advanced Accelerator Experimental Tests.
Both were idle on Friday, June 27, SLAC spokesman Andrew Gordon told the Almanac.
It was still uncertain when the accelerator might restart, Mr. Gordon said.
On Wednesday night, a 911 call came in at about 9:45 p.m. When firefighters arrived on the scene, all they could see was smoke, Division Chief Frank Fraone of the Menlo Park Fire Protection District told the Almanac.
Thick smoke hid the section of the two-mile long building that passes under Interstate 280.
The two-alarm fire was quickly contained. Had it not been, firefighters were prepared to request that the California Highway Patrol close the freeway. "That was our next call," Mr. Fraone said.
The fire was contained by 10:30 p.m. and there were no injuries, Fire Chief Harold Schapelhouman said.
The fire damaged supporting equipment, but not the accelerator itself, Mr. Fraone said.
In fighting the fire, firefighters worked with accelerator staff to determine the source of the smoke, de-energize the accelerator and shut down equipment as needed to allow safe access. In addition, they closed smoke-control doors to isolate the affected area, Chief Schapelhouman said.
The smoke diminished after accelerator staff shut off the electricity to the switch box believed to be at the center of the fire, Mr. Fraone said. The switch box, which measures 8 feet by 10 feet by 3 feet, carried "extremely high voltage" and had high-technology equipment inside it, he said.
Menlo Park firefighters visit SLAC frequently and are "very, very familiar" with the entire accelerator facility, Mr. Fraone said.
Firefighters used seven large mobile carbon dioxide extinguishing carts at the site to suppress the fire, he said. Once the voltage was off, the firefighters extinguished burning insulation and plastic, Mr. Fraone said.
The cause of the fire is under investigation. The second alarm was called as a precaution, Chief Schapelhouman said. "Our crews have been well trained in the protocols and techniques needed to suppress and control fires at this facility."
SLAC representatives meet monthly with the district's prevention bureau and quarterly with Chief Schapelhouman to discuss all incidents at the site.
Stanford University operates the SLAC National Accelerator Laboratory, which opened in 1962, and is one of 10 laboratories overseen by the U.S. Department of Energy Office of Science.
Bay City News Service contributed to this report.