Neutron imaging can reveal how materials are built and how they change, offering exceptional sensitivity to light elements such as hydrogen and lithium. Beams produced at facilities like the Swiss Spallation Neutron Source (SINQ) penetrate deeply into dense metals, enabling non-destructive views of batteries, engines, and even delicate archaeological objects. Yet the same physics that lets neutrons interact in useful ways also makes them hard to steer, focus, or deflect—an obstacle that has constrained resolution and limited what researchers can actually image.
Unlike optical or many X-ray systems, traditional neutron setups rely largely on geometry rather than lenses. Because neutrons of different wavelengths do not naturally converge to a single sharp focus, samples generally must sit close to the detector to keep images crisp. This requirement reduces achievable resolution and effectively caps the size of sample environments that can be studied in detail.
Now, scientists at the Paul Scherrer Institute (PSI) report a breakthrough in Nature Communications: the first practical achromatic neutron lens. “Achromatic” here means the lens brings a broad range of neutron wavelengths to the same focal point, solving the long-standing mismatch between wavelength spread and image sharpness that has stalled advanced neutron focusing.
With this new lens, PSI demonstrates magnified neutron imaging with resolution below twenty micrometers, even when the object cannot be placed near the detector. The team emphasizes that the benefit is not only sharper images, but a new imaging mode that better accommodates realistic experimental conditions.
To test the concept, the researchers imaged a commercial lithium-ion battery while placing it six meters from the detector. They achieved a sevenfold magnification of the layered structure in the wound electrode assembly, illustrating how the technique can expose internal features of functional devices without dismantling them.
Looking ahead, this capability could support studies of components while they operate inside challenging environments, such as furnaces, cryostats, or pressure cells. One envisioned application is tracking structural changes in parts of a running engine, where neutron penetration can access changes hidden from conventional inspection.
The design borrows and extends PSI’s earlier success in X-ray optics. In 2022, PSI developed an achromatic X-ray lens for synchrotron and X-ray free-electron laser facilities. Building on that framework, the neutron lens combines diffraction and refraction-like effects using concentric rings of nickel together with precisely shaped diamond structures.
In the lens, the nickel rings generate a diffraction pattern, while the diamond structures refract the neutron beam; together, these interactions form a magnified image on the detector. Fabrication relied on electron-beam lithography in PSI’s PICO cleanroom, producing nickel features with the finest rings well below 200 nanometers. The diamond refractive elements were manufactured by SYNOVA S.A., and prototypes were tested using X-rays at the Swiss Light Source (SLS) and neutrons at SINQ.
Ultimately, the work shows how closely integrated expertise in neutron imaging, X-ray optics, and nanofabrication can accelerate instrumentation breakthroughs. If future neutron facilities adopt longer beamline requirements, researchers could magnify even more—expanding neutron microscopy and broadening where this lens can be deployed.
Keywords
Neutron imaging, achromatic lens, diffraction optics, lithium-ion batteries, SINQ, X-ray optics, nanofabrication, neutron microscopy, PSI
