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Carbon Based Surfaces with Low Secondary Electron Emission
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Low secondary electron emission materials have significant impact in accelerator and
space technologies. Secondary electrons produced by the residual gas ionization or due to
the irradiation of chamber walls by the synchrotron light influence trajectories of charged
particles inside accelerators. Significant potential difference between the dielectric and
conductive parts of satellites is caused by different secondary electron emission yields induced
by cosmic rays, leading to discharges between different parts of a satellite, resulting
in the malfunctioning of the communication systems and other sensitive equipment. One
of the solutions to these problems is coating surfaces with thin films of amorphous carbon.
Recent studies showed that graphene-based coatings have a potential in further reduction
of secondary electron yields (SEY). For that reason, the deposition of free standing
graphene (i.e. graphene in the form of powder) on technical surfaces of interest in space
and accelerator technologies using Electrophoretic Deposition (EPD) was investigated in
this work. Highly oriented pyrolytic graphite and pure graphene samples were used as
references in order to compare them with graphene coatings produced by EPD. Apart from
SEY measurements, X-ray photoelectron spectroscopy and scanning electron microscopy
of the samples were performed for that purpose. Graphene depositions were successfully
made and the maximum SEY of technical surfaces (stainless steel and copper) was reduced
to 1. In order to achieve these results, various studies were performed concerning the
deposition technique parameters, related to the process and the materials used. Three
different alternatives were also explored.
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Palavras-chave
Accelerator Satellite SEY Graphene EPD XPS