A look at approaches to calculate particle lofting in near-vacuum conditions
DOI: 10.1063/10.0047256
A look at approaches to calculate particle lofting in near-vacuum conditions lead image
Charged particles of dust are a major concern in near-vacuum environments. These particles can adhere to surfaces and contaminate experiments. This has been an issue in space environments for decades, and it reduces yield in the manufacturing of semiconductor components. One way to remove these particles is to apply an electric field, but the required strength of the field is determined by the charge on the particle, which is difficult to determine.
Bouwmans et al. discussed multiple approaches to model the charge of a particle in these environments, and how to use these models to calculate the required force to loft them from a surface.
“The different particle charging models are discussed and an order of magnitude estimation of the particle charge is made and compared,” said author Sim Bouwmans. “The same is done for the forces that act on the particle to see under which conditions a particle can be lofted from a surface.”
The authors describe several models, such as the projected area and shared charge model, the isolated capacitor model, and the insulating particle flux model. The most promising of these is the patched charge model, which uses the presence of microcavities between the particles and the substrate that accumulate charge from the emission of secondary electrons and photoelectrons.
But while these models can be useful, the authors emphasize that they are still mostly theoretical.
“Although the models are doing a nice job, measurements are needed to validate the results,” said Bouwmans. “It would be nice if we were able to measure the charge patches that are used within the patched charge model, but for this, the spatial resolution of present-day measurement methods needs to be increased.”
Source: “Particle charging and lofting from a surface under plasma conditions relevant for space and EUV applications,” by Sim Bouwmans, Vadim Banine, Job Beckers, and Mark van de Kerkhof, Physics of Plasmas (2026). The article can be accessed at https://doi.org/10.1063/5.0347177 .
