An extended study on an advanced method for the cleaning of carbon contaminations from large optical surfaces using a remote inductively coupled low-pressure RF plasma source (GV10x DownStream Asher) is reported. Technical and scientific features of this scaled up cleaning process are analysed, such as the cleaning efficiency for different carbon allotropes (amorphous and diamond-like carbon) as a function of feedstock gas, RF power (from 30 to 300 W), and source-object distances (415 to 840 mm). The underlying physical phenomena for these functional dependences are discussed.
Performs a comparative study regarding the low- pressure (i.e., 5 × 10−3 mbar) RF plasma cleaning rates for O2 /Ar and H2/Ar feedstock gases throughout a wide range of RF powers and source-sample distances which are parameters being relevant for and compatible with applications in the field of cleaning of optical precision surfaces of real-size optics from carbon contaminations made of virtually different carbon allotropes. This study derives several conclusions