Electrical, optical and structural behaviour of fast neutron-irradiation-induced CR-39 SSNTD

The effect of fast neutron irradiation on the electrical, optical and structural properties of CR-39 diglycol carbonate, solid state nuclear track detector, was investigated. DC conductivity measurements were studied in the temperature range 293-413degreesK using solid state samples of the CR-39 polymer. These samples were exposed to neutrons of initial energy levels between 0.8 and 19.2 MeV. Furthermore, the activation energy was measured, at various temperatures, as a function of the neutron energy. It was found that many changes in electrical resistance of CR-39 polymer could be produced by neutron irradiation via the degradation mechanism. Also, at the energy range 6-19.2 MeV the neutron irradiation causes branching that reduces crystallinity and induces further lattice defects that may act as scattering centers and energy barriers for the flow of electric current. Moreover, optical and structural property studies using refractive index measurement and X-ray diffraction were performed on irradiated and non-irradiated CR-39 samples. The results indicate that the neutron irradiation in the energy range 6-12.26 MeV enhances the isotropic nature of the CR-39 polymer samples. (C) 2002 Elsevier Science Ltd. All rights reserved.