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takyon [soylentnews.org] writes:

Movable Silicon 'Lenses' Enable Neutrons to See New Range of Details Inside Objects [nist.gov]

An innovative new way to focus beams of neutrons might allow scientists to probe the interiors of opaque objects at a size range they were blind to previously, allowing them to explore the innards of objects from meteorites to cutting-edge manufactured materials without damaging them.

The method, published today in Physical Review Letters, could convert what historically has been a support tool for neutron science into a full-fledged scanning technique that could reveal details ranging in size from 1 nanometer up to 10 micrometers within larger objects. The approach provides this tool, known as neutron interferometry, with what are essentially its first movable "lenses" capable of zooming in and out on details in this size range — a range that has been difficult to probe, even with other neutron scanning methods.

More precisely, these "lenses" are silicon wafers acting as diffraction gratings, which take advantage of neutrons' wavelike properties. The gratings split and redirect a neutron beam so that the waves bounce off an object's edges and then collide with one another, creating a visible moiré interference pattern [wikipedia.org] representative of the object that is easy for experts to interpret.

Three Phase-Grating Moiré Neutron Interferometer for Large Interferometer Area Applications [aps.org] (open, DOI: 10.1103/PhysRevLett.120.113201) (DX [doi.org])

We demonstrate a three phase-grating moiré neutron interferometer in a highly intense neutron beam as a robust candidate for large area interferometry applications and for the characterization of materials. This novel far-field moiré technique allows for broad wavelength acceptance and relaxed requirements related to fabrication and alignment, thus circumventing the main obstacles associated with perfect crystal neutron interferometry.

Original Submission