In situ Raman spectroscopy a technique to investigate the nuclear material modifications under ion beam irradiation

International audience; Raman spectroscopy is an efficient technique to study the irradiation damage in nuclear materials [1]. Indeed it is possible to investigate the microstructural modifications and to monitor the damage build-up. In order to observe the dynamic evolution of materials under irradiation, in situ Raman setup has been developed on the triple beam chamber of the JANNUS-Saclay irradiation facility. The sample evolution can thus be followed by Raman spectroscopy during single, dual or triple ion beams irradiation. Irradiation damages of several nuclear materials under single ion beam have already been investigated by in situ Raman at JANNUS facility UO2 as nuclear fuel [1-2], SiC [1,3] and Zircaloy as cladding materials [1] and B4C as neutron absorber [4]. It appears that Raman spectroscopy is a good technique to study on-line crystalline phase changes or amorphization of irradiated iono-covalent solids. Moreover, the use of dual ion beam irradiation coupled with in situ Raman has highlighted combined effects of nuclear (Sn) and electronic (Se) energy losses, which can induce additive damage production (as in ZrO2) or competitive recovery processes (as in SiC), in good agreement with Rutherford backscattering channelling (RBS/C) measurements [3].This paper will give a review of these results and present the new in situ Raman results for single and double ion beam irradiations. A particular emphasis will be given to the synergetic Se/Sn effects.[1] S. Miro et al., J. Raman Spectrosc., 45, 481 (2015).[2] C. Onofri et al., NIM B, 371, 51 (2016).[3] L. Thome et al., JAP, 117, 105901 (2015).[4] D. Gosset et al. JNM, 476, 198 (2016).