Structural investigation of Nd-zirconolite irradiated with He⁺ ions

Zirconolite, a potential candidate for the immobilization of actinides was investigated for the induced effects of α-particles simulated through ion beam irradiation. Nd-doped zirconolite pellets (Ca_0.8Nd_0.2ZrTi_1.8Al_0.2O₇) synthesized through two step solid state sintering were irradiated with 30 keV He⁺ ions and analyzed for irradiation induced structural modulations through glancing angle X-ray diffraction technique. Diffraction patterns showed reduction in peak intensity and broadening of peaks with increasing fluence, indicating loss of crystallinity. Though zirconolite didn't amorphize even upon irradiation at the maximum fluence used i.e. 1 × 10¹⁷ ions/cm². Measured lattice strain enhanced with fluence, further suggesting distortion of the structure. (author)