3-D surface morphology measurement of plasma-facing materials using laser speckle interferometry in presence of periodic vibration

Aiming at building the real-time measuring system of surface morphology of Plasma-Facing Components (PFCs) in fusion devices, an optical approach based on Laser Speckle Interferometry (LSI) is in development in our laboratory. To preserve high temporal resolution, the temporal phase shifting approach was introduced. However, this approach is sensitive to vibrations, which decreases the accuracy of morphology measurement. Considering the periodic vibration of the tokamak device itself, it is important to study the influence of the periodic vibration on online surface morphology measurement of PFCs. In this paper, we specify the effects of amplitude and frequency of periodic vibration on surface morphology measurements based on LSI measurement system. Benchmark tests are performed on the Molybdenum (Mo) material, which is commonly used as PFCs in Experimental Advanced Superconducting Tokamak (EAST).