MIT and NASA Researchers Develop a Novel Neutron Microscope

The team’s small prototype neutron microscope is shown set up for initial testing at MIT’s Nuclear Reactor Laboratory.

A group of researchers from MIT and NASA have developed a new microscope that creates high resolution images using neutrons in the place of electrons or light used in conventional microscopy techniques. This new microscope utilizes the same principle used for focusing X-rays to focus neutron beams on a specimen.

The main advantages of neutron instruments is their ability to easily probe inside metal objects and their sensitivity to magnetic properties and lighter elements making them ideal for biological applications. The neutron instruments designed until now were crude imaging systems comparable to pinhole cameras, without efficient optical systems. These instruments were unable to produce images with good resolution. As neutrons have minimal interaction with matter, one of the major challenges faced in neutron instruments is focusing a beam of neutrons on the specimen. This obstacle has been overcome by using mirrors, a technique used to focus X-rays.

A cylindrical mirror of the type developed for neutron microscope with light reflected through it. (Pic: NASA)

The new neutron microscope uses a similar optical system like those used to focus X-rays in telescopes to produce high resolution images. The lens is comprised of several reflective cylinders nested one inside another, offering increased reflective surface area for neutrons. Use of reflective surface to focus neutrons improves the performance of existing neutron imaging systems at least by a factor of 50, resulting in sharper images with smaller instruments,

The first prototype was developed after initially designing and optimizing the concept digitally. A small test instrument developed as a proof of principle was demonstrated using MIT Nuclear Reactor Lab’s neutron beam facility, followed by Oak Ridge National Laboratory and National Institute of Standards Technology at different neutron energy spectrums. The new neutron microscope under development will be helpful for observing and charactering various materials and biological samples and also to study the atomic and magnetic movements inside a material.

Source: MIT