الملخص الإنجليزي
Abstract:
The induced impacts of high doses of gamma irradiations on the optical features of the Makrofol DE 1-1 detector were studied in the ultraviolet and visible range (from 270 to 500 nm). Makrofol DE 1-1 detector specimens were irradiated separately for different doses from 200 to 1000 kGy; step 200. The optical absorbance spectra of the pristine Makrofol DE 1-1, as well as the irradiated gamma-ray samples display two main features: (i) A redshift
with further gamma-ray irradiation doses from 200 to 1000 kGy. This redshift can be ascribed to irradiationinduced defects in polymer material. (ii) A remarkable increment in the optical absorbance for irradiated Makrofol DE 1-1 specimens compared to the pristine one. This increment can be ascribed to the creation of some electronic levels within the forbidden gap resulting from the irradiation process. Moreover, this absorbance increment was employed to assess the degradation percent produced by gamma-ray irradiations. The degradation percent of the Makrofol DE 1-1 increased from 31.73% at 200 kGy to 78.08% at 1000 kGy. The optical band gap, Fermi level and metallization criterion showed decrement behaviors with further doses of gamma-ray irradiations. Also, the percent of changes in optical band gap values were employed to evaluate the degradation of Makrofol DE 1-1 under gamma-ray irradiations. This percent augmented from 15.19% at 200 kGy to 20.25% at 1000 kGy proving the obvious degradation of Makrofol DE 1-1 under gamma-ray irradiations. On the other hand, the number of carbon atoms per cluster, linear and nonlinear refractive indices showed increasing behaviors with
further doses of gamma-ray irradiations.
