A new concept of a microscope using neutrons instead of beams of light has been created by a joint team of Nasa and the Massachusetts Institute of Technology (MIT).
Neutron-based imaging instruments present several advantages – apart from being able to create images with very high resolution, these sub-atomic particles have the ability to penetrate objects, such as fuel cells, batteries, and engines and provide information about the internal structure of these objects.
Moreover, the neutron-based tools can do so even if the studied objects are currently in operation.
Recently, a paper outlining an innovative neutron-microscope concept has been published in Nature Communications.
“The new mirror device acts like the image-forming lens of an optical microscope,” said MIT postdoc student Dazhi Liu, who worked on the project.
In theory, neutron-based microscopes have been known since the 1960s. However, as neutrons barely interact with matter, it has, so far, been difficult to focus the neutron beams and fully harness the potential of this technology.
“Essentially, all of the neutron instruments developed over a half-century are effectively pinhole cameras,” said MIT’s Professor David Moncton. “But with this new advance, we are turning the field of neutron imaging from the era of pinhole cameras to an era of genuine optics.”
To focus the beams, mirrors with coating of nano-materials are being used, reflecting the neutrons at very shallow angles. To increase the surface area available for reflection, the new instrument uses several reflective cylinders nested one inside the other. The resulting device could improve the performance of existing neutron imaging systems by a factor of 50, taking much sharper images and enabling creation of much smaller devices.
The team first created a digital concept, which served as a basis for building a small test instrument that was subsequently used for verification at a neutron beam facility at MIT’s Nuclear Reactor Laboratory.
The researchers now want to build an optimised neutron-microscope system in cooperation with The National Institute of Standards and Technology (NIST). The £0.9bn venture would provide a tenfold increase in the neutron flux. “Given the cost of producing the neutron beams, it is essential to equip them with the most efficient optics possible,” said Moncton.
In the past, a neutron-based imaging instrument has been used by NASA aboard the Chandra X-ray Observatory.