Effect of high radiation doses (MGy) on light Emitting Diodes and optical glasses

Overview & Synopsis

The CAMRAD project responds to the PIA call for proposals from the French National Agency for Radioactive Waste Management with the aim of finding new solutions for radioactive waste management in prevision of its strong increase due to the dismantling of the current French nuclear facilities. The project aims to design a high-definition, radiation-hardened, camera capable to withstand radiation dose levels at least ten times higher than the currently available cameras. This PhD thesis deals with the effects of radiation (up to the MGy) on LEDs allowing the camera to be autonomous in terms of lightning and the optical glasses to be used for the realization of optical system. After a description of CAMRAD, the requirement in terms of lighting are detailed. The main innovations of this work are the qualification at the MGy level of numerous commercial LEDs, post-irradiation measurements of their emission angles and online X-ray measurements. The third part concerns radiation effect on optical glasses. After detailing how Cerium doping of so-called "hardened" glasses protects them from darkening under radiation, we show that there is a lack of literature on the effects of high doses. In order to fill it and to improve the radiation induced attenuation measurements, we have developed an optical set-up allowing to measure the darkening of glasses during irradiation rather than post mortem. We carried systematic measurements on hardened and standard glasses as a function of dose rate and temperature. We have shown that certain standard optical glasses are highly promising for use at MGy dose levels, the followed approach has led to the filing of a patent.