Optical anisotropy in gamma-irradiated fibres under vacuum

The change of optical anisotropy in polymeric fibres by γ-irradiation is suggested to develop a simple method for γ-ray dosimetry. Multiple-beam Fizeau fringes in transmission and in reflection are used in this study for the determination of the refractive indices and birefringence of γ-irradiated Dralon fibres. Variation of the refractive indices of these fibres with the temperature and wavelength of light are also studied. Empirical formulae are suggested to correlate the optical properties of the irradiated fibres with the applied dose. Lorenz-Lorentz equation is applied to calculate the polarizability of the irradiated fibres per unit volume. Illustrations are given by multiple-beam microinterferograms in transmission and in reflection. (author)