High-resolution neutron tomography

A neutron tomography technique with a coordinate resolution of several tens of micrometers has been developed. Our results indicate that the technique resolves details with dimensions less than 100pm and measures a linear attenuation of less than -0.lcm-'. Tomograms can be reconstructed using incomplete data. Limits on the resolution of the restored pattern are analyzed, and ways to improve the sensitivity of the technique are discussed. There are many interesting natural and man-made objects whose internal structures are characterized by dimensions of less than a millimeter. Both X-ray and NMR tomographies are extensively used to study these objects, and the development of neutron tomography is under way. Neutron tomography is attracting attention because of the specific way neutrons interact with matter. Neutron beams interact effectively with both light and heavy nuclei, and at the same time, are very penetrating. Consequently, they can be used under normal conditions and at high pressures or temperatures. In addition, they can be used to study the magnetic properties of materials. New and effective techniques for obtaining neutron patterns in various bands of the neutron spectrum and procedures for reconstructing tomograms are being developed This paper describes a new technique to produce tomograms of objects with dimensions of up to 40" with a resolution better than 100 pm. Two-dimensional 1024 x 1152 neutron patterns are recorded with a single element size of 18 x 18 pm (40 x 40 pm). We have used a new technique for reconstructing the tomogram which is very effective when processing incomplete data or data recorded at a low signal-to-noise ratio. Because of the low luminosity of neutron sources, this is essential as it allows us to reduce the time needed to record a tomogram. Cl, 21.