Mie-Scattering Ellipsometry System for Analysis of Dust Formation Process in Large Plasma Device.

We developed a new Mie-scattering ellipsometry system for the analysis of the generation and transport of dusts in large plasma devices, such as nuclear fusion experiment devices. The system is a rotating-compensator type and consists of polarizer and analyzer modules and a 2-D image sensor. A preliminary experiment was carried out using a small dust plasma cubic chamber. Spherical divinylbenzene polymer particles of 2.25~\pm ~0.05~\mu \textm in diameter with a dispersion degree of 0.1 \mu \textm were injected and suspended in an argon plasma. Light intensity data for 1600 pixels on each image taken 30 times per second were summed as a function of compensator azimuth angle, and then, ellipsometric parameters $\Psi $ and $\Delta $ were determined through Fourier analysis and relational equations. By the comparison of the determined $\Psi $ and $\Delta $ values with the calculated ones based on the Mie theory, it can be stated that they agree fairly well with each other and the measurement method is reliable. [ABSTRACT FROM AUTHOR]