Track recorder scanning by sampling on a fixed grid

Abstract

A technique for scanning track recorders is presented in which track density information is obtained by sampling the surface image at points on a fixed grid, instead of attempting to count the number of tracks present within a given area directly. The strength of this technique lies in its applicability to track recorders having a very high track density and many overlapping tracks (measured by means of the track porosity: the product of track density by the mean track area). A theory is developed in which track porosity is estimated from the fraction of grid points covered by tracks or background features. An experimental test of this theory using alpha tracks in CR-39 indicates that the technique is capable of a precision of 1% in estimating track density or particle fluence for porosities in the range 0.01 to 5 (track densities in the range (0.01−5) × 10 4 mm −2). In principle, this technique can be easily automated, and offers a considerable increase in scanning speed over conventional pattern recognition techniques.