Characterisation of Dust Particles Trapped in Silica Aerogels

Sammanfattning: This thesis involves the study of dust particles trapped in silica aerogel for fusion dust diagnostics purpose. The low velocity impact experiments are done by implanting predefined dust particles into silica aerogel by using a springpiston air gun. The impact experiment results show that the hypervelocity impact model may not suitable for describing the fusion characteristic dust particles. The samples made by impact experiment are analyzed by ion microbeam analysis methods: Rutherford backscattering spectrometry (RBS) and Particle-induced X-ray Emission spectrometry (PIXE). The elements of dust particles are well identified by the X-ray spectra. The X-ray maps clearly show the dust shape. RBS and NRA spectra of an individual particle or a specific region show the depth information of the trapped particles, which is useful for determining the dust velocities. For the interpretation of ion beam analysis result, simulation of dust particles for RBS and NRA are done. The accessible depth for ion beam analysis in silica aerogel can be several hundred micrometers, which is adequate for dust diagnostics.