To whom it may concern, 

The Neutron Scattering Society of America (NSSA) is writing to alert you of an impending lapse in U.S. research at neutron science facilities of critical national importance. The United States played an essential role in the invention of neutron scattering for materials research within the national laboratories, with the technique duly recognized with the 1994 Nobel Prize for Physics to Clifford Shull and Bertram Brockhouse. Neutron scattering is a key scientific tool, providing unique capabilities for developing new materials that will enable medical diagnostics and therapeutics, oil and gas recovery and delivery, nuclear energy, national infrastructure elements such as bridges and transportation, electronics and semiconductors, etc. World leading neutron science capabilities are thus paramount for the U.S. to maintain its economic competitiveness, enable innovation, and create a strategic advantage in security technology as well as the artificial intelligence and the quantum computing revolution. A recent study showed that economic returns to investments from the three current U.S. federal neutron scattering facilities have produced a benefit of $30 billion, with a benefit/cost of 2.67.[1] Key U.S. facilities are listed below. 

• Oak Ridge National Laboratory (ORNL)
  • Spallation Neutron Source (SNS): Outage 2029-2030
  • High-Flux Isotope Reactor (HFIR): Outage 2028-2029, 2032-2034
• National Institute of Standards and Technology (NIST): NIST Center for Neutron Research (NCNR): Outage until 2026
• Los Alamos National Laboratory (LANL): Lujan Center & Weapons Neutron Research Facility (WNR) at LANSCE – Outage 2029-2032

The United States is falling behind its allies and competitors in supporting a resilient strategic portfolio of neutron sources. The U.S. currently operates four neutron sources supporting a total of 48 instruments, while Europe operates 135 instruments, Asia-Oceania operates 73, and China operates 52,  with Asia growing its capabilities aggressively by 75% in the next decade. The U.S. has, to date, failed to invest with similar determination. Lengthy and necessary outages such as the ones planned for all of the abovementioned user facilities will further strain scientists and engineers in both academia and industry, including the United States defense technology sector. As neutrons serve a central role in the National Stockpile Stewardship program, this constitutes a hazard to national security. A complicating matter lies in the fact that the these facilities are funded through varying sponsors at the Department of Energy Office of Science, the Department of Commerce, the National Nuclear Security Administration, and the National Science Foundation. Sponsors must approach the neutron source portfolio holistically to ensure operational resilience and maintain the scientific leadership of our country. We strongly endorse:

1) Additional support for facilities at ORNL. The Second Target Station (STS) project at ORNL is absolutely essential to the U.S. neutron community. The continued expansion of foreign capabilities with the completion of the European Spallation Source and the Chinese Spallation Neutron Source highlight the danger of the U.S. falling behind in global materials research leadership, and neutron scattering leadership and science moving abroad. The reactor-based HFIR facility at ORNL is a keystone of the U.S. source portfolio and requires significant investment in its science capabilities[2] and the eventual transition to low-enriched fuel.[3]

2) Increased support for NCNR. The NSSA is fully supportive of expanding the operations of the NIST NCNR and the next-generation NIST Neutron Source.[4] With the planned installation of the new cold source, the NCNR will have world-leading capabilities for high-resolution neutron scattering for decades to come. The deployment of world-leading facilities must be matched by appropriate increases in personnel funding for both reactor operations and scientific support.

3) Expand neutron access at LANL. Although, the Lujan Center and WNR have a 50 year history as productive neutron scattering facilities, they currently are not broadly accessible by industrial and academic communities. Investments in rebuilding the front end of the LANSCE accelerator (LAMP project) are imperative. In the interim, the Lujan facility may serve as an instrument development testbed to empower scientists to harness the future capabilities of the STS at ORNL, allowing for additional U.S. neutron development capacity without unduly burdening the ORNL user program. Ultimately, the Lujan center should be relaunched as an open basic science user facility during the outages at other sources and before the STS is commissioned.

4) Support University-based neutron sources. The current and planned shutdowns of neutron scattering sources in the U.S. has put tremendous strain on the neutron scattering community. The national oversubscription problem has skyrocketed across all of the abovementioned facilities. It is important to provide scientists with access to university neutron sources for experiment capability and domestic workforce development. Reliable funding of university-based reactors is, thus, essential.

Finally, the nation must build new neutron sources, not only to broaden capacity but also to reinforce operational resiliency. The number of sources in the U.S. has dropped over the past three decades, while our competitors in Europe and Asia have been building new state-of-the-art facilities. As U.S. reactor-based sources were built in the 1960's, investment in planning for a new reactor-based neutron source should be started immediately.

We hereby implore your office to take formative steps to integrate strategic operations and funding structures of our nation’s key facilities. We must ensure a robust and resilient national neutron scattering facility portfolio that enables the science and engineering advancement on which this nation builds its preeminent position in the world. Decisive action on this front is a national strategic imperative.

Sincerely yours,

Adrian Brügger, Ph.D. 
President of the Neutron Scattering Society of America
Director, Adjunct Associate Professor & Research Scientist, Columbia University

[1] “Assessment of the retrospective and prospective economic impacts of investments in U.S. neutron research sources and facilities from 1960 to 2030: Final report.” RTI International (2024)
[2] "Scientific Justification for a U.S. Domestic High-Performance Reactor-Based Research Facility" BESAC Report (2020)
[3] "Neutrons for the Nation" APS POPA Report (2018)
[4] “Neutrons for the Future” Special Publication (NIST SP) - 2100-07 (2024)