A new automatic spark counting system

The design and construction of the University of Tehran Automatic Spark Counter (UTASC) are described in detail. The system is used to detect the etched fission fragment tracks in thin plastic SSTRs. The track-detection mechanism is based on scanning concentric circles of the specimen rather than the usual XY scanning methods. The circumference of the circle can be traversed to within +- 2 μm and the reproducibility of the rotation is to within 0.0010. The difference in radii of the concentric circles is preset in the range of 1 to 99,999 μm. The UTASC system is capable of obtaining reliable results for track densities up to 2 x 104 tracks cm-2 for normal-incidence irradiations. The counting efficiency of the system is about 97% compared with an optical microscope, for track density up to the just-mentioned figure. (author)