Second Target Station: Additional neutron source will meet emerging science challenges
Oak Ridge National Laboratory (ORNL) is moving forward with plans for a major upgrade to the Spallation Neutron Source (SNS) to add a Second Target Station (STS) to address emerging science challenges.
Neutron scattering is an essential technique for advancing materials research that supports the US economy and offers solutions to challenges in energy, security, and transportation. It provides information that cannot be obtained using any other research method.
Since reaching a major milestone in November 2020 when the US Department of Energy (DOE) officially gave the project Critical Decision 1 (CD-1) approval, the project has continued working on the next phases of design and development.
The project received CD-2/3B approval for subproject 1 in September 2026, approving the start of construction. This authorization will allow the construction of the STS Conventional Facilities, the procurement of Accelerator Systems hardware, and procurement of select components of the Target Systems and Instrument Systems.
The STS Project previously received CD-3A approval in June 2025 for preparing the STS site. This work included surveying and marking the STS site, mass grading, relocation of the SNS spoils mound, subsurface characterization through pothole digging and probe‑hole drilling and building a construction access road to reduce construction traffic near SNS. This effort is expected to complete in mid CY2027 and clears the way for construction to begin under the newly approved CD‑2/3B authorization.
At ORNL, scientists from around the world access two neutron sources with complementary capabilities to better understand the materials important in physics, biology, chemistry, materials science, and engineering. The SNS provides the most intense, pulsed accelerator-based neutron beams in the world, while the High Flux Isotope Reactor (HFIR) is the highest flux reactor-based source of neutrons for research in the United States and provides one of the highest steady-state thermal and cold neutron fluxes of any research reactor in the world.
The capabilities of the STS will complement those of the SNS First Target Station (FTS) and HFIR, by filling gaps in materials research that require the combined use of intense, cold (longer wavelength) neutrons and instruments that are optimized for exploration of complex materials. Together, these three facilities form an unbeatable combination that will maintain US global leadership in neutron science capabilities. The STS will feature:
- The ability to simultaneously probe the structure and function of complex materials across broader length and time scales, contributing to the understanding and design of novel, complex materials.
- Neutron beams ideal for exploiting the magnetic interaction of neutrons with matter to unravel the structure and dynamics arising in complex magnetic materials.
- High-brightness cold neutrons that are suited for experiments with smaller samples than what is currently possible using the SNS First Target Station (FTS).
- Experiments that will be complemented by other ORNL capabilities, such as high-performance computing (HPC), that can contribute to all areas of research.
