Applications of neutron induced particle tracks for materials analysis

Abstract

Thermal neutrons are captured by several elements which emit charged particles as reaction products. These particles leave etchable damage tracks in detector materials placed against a sample, creating a map of the distribution and concentration of the target element. The most common applications are for U using fission tracks and B using alpha tracks. Distributions of Li, N and possibly S and O can also be mapped. Applications discussed here include B in metals and coatings, Li in Al, N in polymers and nitrided glasses and U in contact with O-ring seals. Detection limits are better than 1·10⁻¹¹ g/g U, 1·10⁻⁹ g/g for B, 1·10⁻⁶ g/g for Li and 0.1 wt.% for N. Spatial resolution for mapping is about 25 μm.