Modeling and Characterization of Fiber Bragg Grating for the Radiation Dose Measurement
Hazem M. M. El-Hageen
As Fiber Bragg Gratings (FBG) sensors are already in use to detect variations in temperature, pressure, stress strain and vibration, the progression through to radiation measurement is conceivable. In nuclear environments when FBG’s are exposed to ionizing irradiation results have shown changes in the Bragg parameters, although the exact causes are still unclear. A theoretical model of FBG is applied to evaluate the radiation-induced change of refractive index and shift of Bragg wavelength as critical parameters in contributing to the performance of FBG dosimeter. The model include extracting transfer function of The FBG reflectivity and its’ pulse response under radiation effects. The validation of the proposed model is investigated, its parameters are simulated and compared with previous measured values, the results are so close to real measured data. The model provides a deeper analysis of the experimental results and the ability to extrapolate and predict the changing of the characteristics of FBG under radiation to use it as a radiation sensor under low and high total gamma dose (0.1-1MGy).
Keywords: Fibre bragg grating, coupled mode theory, gamma radiation, radiation sensors