OPTICAL RARE-EARTH DOPED FIBER LONG PERIOD GRATING BASED IONIZING RADIATION DOSE SENSOR DEVICE

This invention relates to a sensor device consisting of long period gratings made of rare-earth doped double clad fiber, which is written by CO2 laser irradiation while the fiber is held static, for gamma dose measurement in the range of 150 Gy-2.5 kGy, extendable to 20 kGy, which measurements are real-time and can be from remote locations. The sensor device has high wavelength dip shift sensitivity of at least 2.8 nm/kGy, and its radiation-induced changes are near permanent. The gratings demonstrate negligible temperature sensitivity and the shifts recorded show negligible annealing at room temperature.