Track Overlap Research Articles

A microcomputer-based solid-state nuclear track image analyzer

A microcomputer-based image processing system has been developed to use with solid-state nuclear track detectors for number counting, area measurement, and location identification. The image digitizer is designed to interface with a microcomputer and a standard black and white TV camera for data acquisition. A spatial dependent segmentation algorithm is proposed for track identification under nonuniform illumination and the low track-pixel population conditions. The system has been tested using Lexan samples irradiated by a Cf-252 spontaneous fission source. The counting accuracy is approximately 3% with a long term stability of 5%. Efficiency calibration was performed using samples with track densities up to 104/mm2. Results indicate that the proposed track identification scheme tends to reduce the track overlap effect and the system behaves as a nonparalyzable counting system. For track densities below 3000/mm2, either a paralyzable or a nonparalyzable counter model can be established with an accuracy better than 0.5%. For track densities below 1500/mm2, the track registration efficiency is in good agreement with manual counting results.

Effect of particle fluence on track diameter and response of electrochemically etched SSNTD

Track diameter as a function of particle fluence is given for electro-chemically etched fission fragment tracks. It is shown that high particle fluences decrease the developability of electrochemically etched tracks. Therefore the dependence of sensitivity on particle fluence was studied for polyester and poly(allyl diglycol carbonate). Continuously decreasing sensitivity was found even in the case when track overlap does not occur. An idea for correct interpretation of the response is suggested.

Ion Implantation Damage in Silicate Glasses

ABSTRACTIon implantation is a rapid technique for simulating damage induced by α-recoil nuclei in nuclear waste forms. The simulation has been found to be quite good in TEM comparisons with natural α-decay damage in minerals, but leach rate differences have been observed in glass studies and were attributed to dose-rate differences. The similarities between ion implantation and recoil nuclei as a means of producing damage suggest that insights into the long-term behavior of glass waste forms can be obtained by examination of what is known about ion-implantation damage in silicate glasses. This paper briefly reviews these effects and shows that leaching results in certain nuclear waste glasses can be understood as resulting from plastic flow and track overlap. Phase separation is also seen to be a possible consequence of damage-induced compositional changes.

Analysis of Automatic Fission Track Scanning in Solid-State Nuclear Track Recorders

A computer controlled microscope has been developed for the automatic scanning of fission tracks in solid-state track recorders. Emphasis has been placed on the attainment of absolute accuracy comparable to that already demonstrated in manual track scanning. Analysis of automatic fission track data is considered in detail. It is demonstrated that track overlap or pileup can be accurately described within the framework of the paralyzable counter model. Absolute calibration of this system has been successfully carried out for Makrofol solid-state track recorders. Absolute fission rate measurements by automatic track scanning of Makrofol have been established with at least as high an accuracy as that of manual track scanning. Limitations due to effects of nonuniformity in fission track density have been estimated. Extension of these precise capabilities to mica solid-state track recorders has been attempted. In contrast with Makrofol, unresolved difficulties have been encountered in the automatic scanning of mica.