High Quality Content by WIKIPEDIA articles! Ion tracks are created by swift heavy ions penetrating through solids. They correspond to transformed zones larger than 6 nanometers in diameter and can be studied by Rutherford Backscattering Spectrometry (RBS), Transmission Electron Microscopy (TEM), Small-Angle Neutron Scattering (SANS), Small-Angle X-ray Scattering (SAXS) or gas permeation. Ion tracks can be selectively etched in many insulating solids, leading to cones or cylinders, down to 8 nanometers in diameter.