Influence of irradiation of CR-39 with α-particles on the optical dispersion parameters: Role of chemical etching to develop nuclear tracks

CR-39 polymer films are irradiated to alpha particle for two exposure times 5 and 10 min. The set of detectors produced in the studied films after irradiation are chemically etched for 2 h up to 15 h. The measured average diameter of the growing tracks revealed the presence of three sets of tracks due to etching. Furthermore, the decrease of the measured transmission against etching time is analyzed using optical opacity. Furthermore, fitting the measured absorption coefficients illustrated that the direct optical energy gap is the most probable transition. The increase of the calculated Urbach energy against etching proved that the growing tracks could be treated as structural defects. The values of the coordination number of the considered polymer showed an increase with the maximum at etching time 7 h which indicates an increase of compactness of the considered films. The wavelengths at zero material dispersion, lambda(c), showed an increase against irradiation dose by a ratio of 8-9%. Indeed, etching times showed an increase in lambda(c) up to 7 h followed by a decrease up to 15 h. This means that considered irradiated and chemically etched CR-39 could be used to transmit optical data in low dispersion optical fibers in comparison with silicates and germinates.