An Electron Beam Profile Instrument Based on FBGs

Along with the dose rate and the total irradiation dose measurements, the knowledge of the beam localization and the beam profile/ energy distribution in the beam are parameters of interest for charged particles accelerator installations when they are used in scientific investigations, industrial applications or medical treatments. The transversal profile of the beam, its position, its centroid location, its focus or flatness depends on the instrument operating conditions or on the beam exit setup. Prove-of-concept of a new type of charged particle beam diagnostics based on FBGs was demonstrated. Its operating principle relays on the measurement of the central wavelengths change for an array of FBG sensors as function of temperature, following their exposure to an electron beam. Periodically, the irradiation of sensors is stopped and they are forced cooled to a reference temperature against which the temperature influencing each sensor during beam exposure is evaluated. Commercial available FBGs and FBGs written in radiation resistant optical fibers were tested under electron beam irradiation in relation to this application.