A Reliable Simple Automatic Micrometric Scanner for Counting the Fission Fragment Tracks

摘要

The design, construction and application of a counting system using simple Automatic Micrometric Scanner (AMS) device for Fission Fragment Tracks (FFT) are described in detail. The system is used to detect the etched fission fragment tracks in thin plastic Solid State Track Recorders (SSTRs) (12 $mu$m thickness). The track-detection mechanism is based on scanning concentric circles of specimen rather than the usual XY scanning methods. The circumference of the circle can be traversed to within ${pm}2 mu$m and the reproducibility of the rotation is within 0.001 $^{circ}$. The difference in the radii of the concentric circles is preset in the range of 1 to 99 999 $mu$m. The system is capable of obtaining reliable results for the track densities up to $2 times 10^{4}$ tracks/cm$^{2}$ and normal-incidence irradiations. The counting efficiency of the system is about 97% compared to visual methods employing a microscope equipped with CCD device, gas permeation technique and spark gas chambers for track densities up to the just-mentioned figure.