Characterization of dust collected in EAST after 2019 campaign

Dust presented in experimental advanced superconducting tokamak (EAST) with mixed plasma-facing materials has been collected and characterized for the first time. Dust at different positions in the vessel was collected by vacuum cleaner after the first experimental campaign in 2019. The shape, composition, and size of dust particles have been analyzed using different methods. About 80% of the total number of dust particles have size between 20 and 80 μm, and most of dust particles are spherical, while schistose shape, columnar and irregular shape were also found. With the help of energy-dispersive x-ray spectroscopy different elements of dust have been identified, which is generally consistent with the different plasma-facing components in EAST. Both x-ray fluorescence and inductively coupled plasma emission spectrometer are complementary methods for measuring the dust composition quantitatively. It was found that the major components of dust were lithium dust in the form of lithium carbonate and lithium hydroxide, which is due to the routine lithium wall conditioning during EAST operation.