The Spallation Neutron Source (SNS) at the Department of Energy's Oak Ridge National Laboratory set a world record for accelerator-driven neutron research when its linear accelerator reached an operating power of 1.55 MW, improving on the facility’s original design capability of 1.4 MW. That higher power means more neutrons for researchers who use the facility for neutron scattering research to reach materials science advances, ORNL announced recently.
The SNS produces neutrons by accelerating protons down a 300-meter-long linear accelerator and into a liquid mercury target. The resulting “spall” of neutrons is routed to 20 surrounding research instruments, each optimized to carry out experiments on the atomic structure and behavior of different materials under different environmental conditions. As the incoming neutrons scatter off atoms within the test sample, they are captured by high-speed detectors that supply data for analysis. Since the SNS was completed in 2006, it has been available to researchers from around the world as a DOE Office of Science user facility.
Higher power: The SNS’s 1.55-MW power level was reached after additional accelerating systems were installed as part of the ongoing Proton Power Upgrade project at the accelerator. The Proton Power Upgrade will continue to push the linear accelerator’s power capability up to 2.8 MW—twice its initial power of 1.4 MW. This will increase the number of neutrons available for experiments at the existing target station and power a planned Second Target Station. The Second Target Station would provide the world’s brightest “cold” (low energy) neutrons, according to ORNL, enabling experiments that are either not currently feasible or not routine, including experiments on smaller or less concentrated samples, or samples under more extreme environmental conditions.
“Reaching 1.55 megawatts at the Spallation Neutron Source is an exciting step toward completing the Proton Power Upgrade project, and it has been made possible because of the outstanding dedication and commitment of every member of the Neutron Sciences team at Oak Ridge National Laboratory,” said interim ORNL director Jeff Smith. “It is an incredible privilege to work at ORNL and be part of the neutron science community. There are many cheering on our work around the world as we enable SNS to break new ground across science.”
HFIR: ORNL is also home to the High Flux Isotope Reactor (HFIR), which provides an 85-MW steady-state neutron beam for neutron scattering experiments. Completed in 1965 to produce transuranic elements, including plutonium and curium, HFIR was refurbished in 2007 after the SNS came on line. Today, HFIR is operated as a source of both thermal and cold neutrons for neutron scattering and for isotope production, irradiation materials testing, and neutron activation analysis.