After being shut down for more than a month because of multiple problems, the Spallation Neutron Source has resumed production of neutrons for research experiments.
Kevin Jones, director of the Oak Ridge National Laboratory’s Research Acceleration Division, said the SNS systems were restarted over the weekend — with neutron production resuming shortly before 6 a.m. Sunday.
The Spallation Neutron Source is one of the world’s premier facilities for using neutrons to explore the properties and structure of materials, and it attracts scientists from around the United States and abroad. About 150 experiments reportedly had to be rescheduled because of the unplanned outage at the ORNL research complex atop Chestnut Ridge.
The SNS was shut down in early September — only a few weeks after returning to operations following a scheduled shutdown for maintenance and upgrades — because of the premature failure of the vessel that holds the mercury target. The target vessel was replaced, but another problem — a water leak in a section of the facility’s linear accelerator — cropped up before the systems could be restarted.
The SNS team worked overtime to make the necessary repairs, and Jones said the restart actually occurred about a week ahead of the target date of Oct. 27.
“We were presented with fewer unknowns than expected,” Jones said. Also, the refurbishment of the front-end radio-frequency (RF) accelerator components were conditions to “acceptable levels” sooner than expected, he said.
During operations, The SNS produces trillions of neutrons every second when the target is struck by powerful pulses of a proton beam. Streams of neutrons are then diverted into channels for use at the different research stations.
Following restart, the initial uses of the SNS systems will be researchers who are within driving distances of Oak Ridge facility, Jones said. “This would be a blend of ORNL staff and other users who can readily get to the SNS,” he said.
“Our users that were originally scheduled on and after Oct. 28 were not affected and plan to be here for their experiments,” Jones said. “We will run our planned and published schedule through Dec. 23.
The ORNL official said the team is evaluating options to recover some of this fiscal year’s lost time by modifying the operating schedule after Jan. 1.