VENUS instrument at ORNL delivers first neutron imaging results for users

The Versatile Neutron Imaging Instrument (VENUS) has moved from development to operation, welcoming its first users at the Spallation Neutron Source, a Department of Energy Office of Science user facility at Oak Ridge National Laboratory.

Among the first to test its capabilities were Stuart Miller, principal scientist at the Nevada National Security Sites' Los Alamos Operations office, and Dayakar Penumadu, Chair of Excellence with the Institute for Advanced Materials and Manufacturing at the University of Tennessee, Knoxville. Miller and Penumadu have used neutron imaging in their research for decades as long-time colleagues of Hassina Bilheux, instrument scientist for VENUS at the Spallation Neutron Source (SNS) and MARS at the High Flux Isotope Reactor (HFIR).

Their work at VENUS marks a pivotal moment for neutron imaging and its applications in engineering, materials science and forensic analysis.

"It's a privilege to be here and work with this state-of-the-art beamline, especially since this is my project's final stage," Miller said. "It's an incredible opportunity to get these first images and demonstrate this new technology. VENUS is truly the forefront of neutron imaging."

Sharper images, faster experiments

VENUS was designed from the start with advanced AI capabilities for faster imaging in fewer measurements. VENUS was also built for state-of-the-art 3D imaging, a vision now realized through Miller's project. His project consists of a dual-camera system that captures individual neutron scintillation events in 3D within a transparent scintillator, which is a material that converts radiation to light.

"We're seeing a 10 to 100 times improvement in detection efficiency, which means faster imaging and less beam time needed for each experiment," Miller said.

Miller's patent-pending technology and the transparent scintillator materials - developed by ORNL's Detectors group - provided the first test of VENUS's performance and scalability through user-proposed experiments.

"Stuart and his team needed to see neutrons at different energies, which is exactly what VENUS is designed to do," Bilheux said, instrument scientist for VENUS. "So, it was a perfect match between what he needed and the capabilities we built."

Penumadu compares imaging to what happens with a flashlight. The further away you go from an illuminated object, the more the light spreads out. In terms of neutron imaging, this spreading causes an image to appear blurred. However, Miller's dual-camera system allows researchers to pinpoint where neutron events occur, eliminating the blur.

"Now we can retain high spatial resolution, regardless of whether the interaction occurs at the surface or deeper within a thicker scintillator," Miller said. "This technique ensures that we can determine where any neutron interacts within a 50-micron range, which is extraordinarily precise. VENUS was the key to testing and verifying this system."

Training the next generation of neutron users

The VENUS team demonstrated Miller's imaging system for the first time with both thermal and cold neutrons using materials Penumadu brought, which included a carbon fiber composite. VENUS allowed Penumadu to understand the state of strain in the material he brought for study.

Penumadu, also a long-time user of SNS, brought students on this trip to the lab, as he usually does.

"For me, the real goal is ensuring the next generation is aware that these tools exist-so that when they encounter problems in their research, they can call on experts here to help and make meaningful progress," Penumadu said.

VENUS is one of 19 instruments in the SNS User Program, the most powerful pulsed accelerator-based system in the world. The SNS celebrates 20 years in April 2026. HFIR is another neutron source at ORNL. Completed in 1965 and operating at 85 megawatts, HFIR's steady-state neutron beam is the most powerful reactor-based neutron source in the United States.

Each year, researchers from all over the world visit ORNL to conduct neutron scattering research on the 31 instruments at both facilities within the User Program. Beam time is granted through the User Program and is completely free of charge with the condition researchers publish their results to make them available to the scientific community.

SNS is a DOE Office of Science User Facility.

UT-Battelle manages ORNL for DOE's Office of Science, the single largest supporter of basic research in the physical sciences in the United States. The Office of Science is working to address some of the most pressing challenges of our time. For more information, visit energy.gov/science. - Sumner Brown Gibbs