FLEXIBLE ANALYSIS OF ETCHED NUCLEAR-PARTICLE TRACKS

A highly flexible method has been developed for the analysis of etched nuclear particle tracks, optimised to yield the highest precision output. The technique is applied to alpha-particle and proton tracks in CR-39. Any combination of the output parameters may be calculated given sufficient degrees of freedom: total particle range, dip angle, bulk etch rate, track etch rate scale factor, and the etch induction time. The analysis works exactly using any arbitrary track etch-rate-range curve. The technique uses any number or combination of the measurable parameters of an etched track: major and minor axes M(j) and M(i) of the opening mouth; the total projected length X(t); the track depth Z(t); the radius of the etched out end M2; and the mean optical density D(i). The parameter D(i), readily measurable by automated systems, greatly extends the data available for alpha-particles and protons. The analysis is fully integrated with an image analysis system to provide a fully automatic system to scan, identify, measure and analyse track etch pits, and includes compensation for range straggling and multiple Coulomb scattering. Thus, for the first time, fully automated high resolution scanning can be carried out on all types of tracks, including protons and alpha particles. A resolution close to the straggling limit is achievable. The combined system can cope with track densities typically between 2 tracks cm-2 and 10(6) tracks cm-2.