Dislocation activity of micro-bubbles in sapphire shaped crystals detected using Synchrotron Radiation

We present the approach to evaluating critical strains for the basal plane slip in sapphire ribbons. Using computer simulations to calculate the elastic sresses around a spherical micro-bubble, we have obtained actual bubble size which is below the resolution limit of conventional optical microscopes. Matching synchrotron phase-contrast images and x-ray diffraction topographs confirms the generation of dislocations at the bubbles.