Over the last 25 years, polymer track detectors have found increasing application for particle detection. It was found that radiation damage of heavily ionising particles such as alpha particles can be changed to visible tracks not only in inorganic solids such as in mineral crystal and glasses, but also in organic solids. Alpha particle tracks were first observed in cellulose nitrate and cellulose acetate butyrate. Later in was found that other plastics such as bisphenol-A polycarbonate and allyl diglycol carbonate are also sensitive to alpha particles damage. Such damage exists in the form of latent tracks which can be made visible by chemical etching.
Polymers are the only substances in which etching reveals tracks of alpha particles.
The formation of latent tracks is due to the interaction of the passing alpha particles and the atoms of the polymer. This process occurs in a very short time of the order of 10 -14 s for 1 MeV alpha particles. It is essentially an electronic collision cascade process which spreads out from the particle trajectory and leaving behind a positively charged plasma zone producing chemically activated molecules outside this zone. The latent track is not visible under an optical microscope. To render the latent track visible, chemical etching is usually performed.