Radiation distribution sensor with optical fibers for high radiation fields

Radiation distribution sensors with their feasibilities have been described in earlier works. However, due to large radiation induced transmission los ses in optical fibers, especially in the visible wavelength region, it has been difficult to apply these techniques to high radiation fields. In this study, we proposed a new concept of optical fiber based radiation distribut ion measurements with near infrared (IR) emission. Near IR scintillators we re attached to the ends of optical fibers, where the fibers were bundled an d connected to an N-MOS line sensor or a cooled CCD camera. Front the measu rements of each area density; the radiation levels at the positions of the scintillators can he known. The linearity between the gamma dose rate at ea ch scintillator and the registered counts has been examined. For correcting the radiation induced loss effects; we applied the Optical Time Domain Ref lectometry technique to measure the loss distribution and from the results, a possibility for correction of the loss effect has been demonstrated. The applicable dose rate range was evaluated to be from 0.1 to 10(3) Gy/h. Thi s system can he a promising tool as a flexible dose rate distribution monit or in radiation facilities like nuclear plants and accelerator facilities.