Nuclear-Particle-Track Identification in Inorganic Solids

The unique feature of track-recording plastics which allows them to be used to identify particles is that the chemical rate of attack $V_T$ along a track is an increasing function of ionization rate. This same characteristic is shown to extend to inorganic dielectric solids. The relation between $V_T$ and ionization rate has been measured for five different glasses, using fission fragments of different energies. The variation of $V_T$ is least for ordinary lime glass and much the greatest for a phosphate glass, suggesting that the latter should be useful in resolving atomic numbers and energies of fission fragments and other very heavy, energetic nuclei. Equations are derived that allow the shapes of etched tracks to be calculated as a function of etching time and particle ionization rate. The calculations agree well with recent experimental results.