(1976). Nuclear Tracks in Solids (Principles and Applications) Nuclear Technology: Vol. 30, No. 1, pp. 91-92.

Nuclear Tracks in Solids (Principles and Applications)

Effects of neutron irradiation on optical and chemical properties of CR-39: Potential application in neutron dosimetry.

A set of Makrofol DE 1-1 polymeric samples was irradiated to different gamma doses. The dielectric response of irradiated polymers was investigated at a wide range of frequencies at room temperature. The modification induced in optical properties include the optical band gap (Eoptical), number of carbon per cluster (M), number of carbon per length (N), and refractive index (n) for irradiated samples were studied as well. The dielectric constant (έ), dielectric loss factor (e˝), loss tangent (tanδ), the ac electrical conductivity (σac), and impedance (Z) were measured in the frequency range from (100) Hz to (100) MHz. The optical band gap energy and its corresponding parameters for the samples were evaluated using ineffective thickness method (ITM). Gamma-ray irradiation had a considerable effect on the optical band gap energy for Makrofol DE 1-1 polymer detector film, which decreases from 4.20 to 3.96 eV and 4.35 to 4.16 eV for indirect and direct allowed transitions in ITM method, respectively, while it decreases from 4.40 to 4.20 eV in DITM method as a result of γ-ray dose increases. (n) of all studied samples is considerably high. (N) and (M) for the direct transition are lower than that for the indirect transition and their values increase with increasing gamma dose. The results reveal that Makrofol DE1-1 polymer can be used as gamma dosimeter. Furthermore, Makrofol DE1-1 has much greater resistance to radiation damage; the attained results suggested strongly the applicability of Makrofol DE1-1 polymer to be used in medical products applications and suitable for optoelectronic and photoelectric devices.

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Electrical and optical properties of Makrofol DE 1-1 polymeric films induced by gamma irradiation

Modifications in the optical and thermal properties of a CR-39 polymeric detector induced by high doses of γ-radiation

The UV–VIS (ultraviolet–visible) spectra and etching characteristics of poly allyl diglycol carbonate (PADC, a form of the CR-39 polymer) detector films after exposure to UV radiation for various times have been studied. Etching experiments were carried out on the UV-exposed CR-39 detectors after alpha particle and fission-fragment irradiation using a 252Cf source. The bulk and track etch rates were measured using the alpha and fission-fragment track diameters, and the sensitivity and the detection efficiency were also determined. The optical band gap for both indirect and direct transitions was calculated based on the absorption edge of the UV spectra of the pristine and variously UV-exposed detectors. The optical band gap evidently indicates a gradual change in the optical properties of the CR-39 detector that is induced by the UV radiation. This study shows that the UV-exposed CR-39 detectors were demonstrated to be highly sensitive to alpha particles, but proved to be somewhat less sensitive to the fission fragments.

R.A. Mohamed

Papers

Study of the optical properties of etched alpha tracks in annealed and non-annealed CR-39 polymeric detectors

Ultraviolet radiation-induced modifications of the optical and registration properties of a CR-39 nuclear track detector