In this paper we propose a soft-X-ray method to characterize dust accumulation or layer formation on a given substrate. The method determines the differential absorption based on the X-ray lines emitted from the substrate by fluorescence as a result of film or powders deposited on the substrate surface. We have chosen to use molybdenum as the material for the substrate because it is used in present-day tokamaks and it is being considered as material for the first mirror. It also offers the advantage of having two strong lines, well separated in energy: the L-shell emissions centered at ∼2.3 keV and the Kalines at ∼17.4 keV. The transparency of the layer can be then measured at 2.3 keV, provided the Kaline is unaffected. The feasibility of the proposed method was clearly demonstrated in laboratory experiments, providing estimations of the thicknesses that can be detected, for a number of relevant elements for fusion devices (Be, C, Fe, and W).
All Science Journal Classification (ASJC) codes
- Civil and Structural Engineering
- Nuclear and High Energy Physics
- Nuclear Energy and Engineering
- Materials Science(all)
- Mechanical Engineering
Pacella, D., Pizzicaroli, G., Mazon, D., & Malard, P. (2010). A method for detecting layers or dust deposited on tokamak surfaces. Fusion Science and Technology, 57(2), 142 - 151. https://doi.org/10.13182/FST10-A9368