Particle Tracks and Fission Tracks

Abstract

A fast charged particle, when passing through an insulating solid, creates a narrow trail of damage along its trajectory. This damage trail persists in the solid after the particle has come to rest and is called a charged particle track or nuclear track. The solid in which the tracks are registered is commonly called the detector. The length of a nuclear track is variable, ranging from less than 1 μm to several mm, depending mainly upon the charge and energy of the particle and upon the composition of the detector (glass, minerals, plastic). The width of the track is largely submicroscopic, in the order of a few nm. The trail of damage forms a site of preferential attack for chemical reagents. Chemical etching enlarges the tracks to such an extent that they become visible under an optical microscope (Price and Walker, 1962e,d). The unetched track which cannot be observed with an optical microscope, is commonly called the latent track. Optical revelation of latent tracks by chemical etching forms the subject of the next chapter.