Calculation of Optical Energy Band Gap of CR-39 SSNTD irradiated by Alpha particle


The effect of alpha particle irradiation on the optical absorption in nuclear track detectors (CR-39)has been studied . These detectors have been irradiated with different doses. The optical absorption has been measured using the ultraviolet-visible (UV-1100) spectroscopy, this irradiation results in Shifting the peaks of the optical absorption. The values of Urbach energy have been calculated from the position of steady-state optical band gap energy, and the values of this energy for standard sample and the which irradiated in indirect influence where it is found to be(3.9eV) before irradiation and the least value after irradiation(3.2eV).In case of the indirect influence, it is found to be respectively before irradiation (4.2eV)and after irradiation (3.8eV) . From these results we can reveal that ,the values of energy gaps in direct –coincidence greater before and after irradiation from those in indirect. The energy gap is inversely proportional to the absorbed doses ,i.e the energy decreased with increasing the dose, and this because the irradiation Effects. Finally, the number of carbons atoms have been determined in each case for the optical energy gaps.