In 1959, it was discovered that mica, that was exposed to fission fragments, showed "nuclear tracks" when viewed under an ordinary microscope. This discovery led to a new class of nuclear physics detectors as well as a wide range of practical applications in earth science, oceanography, biology, medicine, archaeology, and space science.

By exposing thin sheets of plastic or other material to massive ions, tracks can be made through the material and then etched to make very fine "micropore" filters (30 nm to 8 mm hole size). These have been made at reactors since about 1970 and are used primarily in the biomedical field, with other applications in geophysics, meteorology, and brewing.

Another use for these sheets of plastic is to measure radon levels. By counting the number of ion tracks left in the plastic, one can measure the radon concentration.