Few-nanometer-wide carbon toroids in the hydrocarbon films deposited in tokamak T-10

Measurements of X-ray scattering by the hydrocarbon films, deposited in tokamak T-10, in the range of scattering wave vector's modulus q∼5÷70nm-1 are interpreted via solving an optimization problem within a broad class of carbon nanostructures (tubules, fullerenes and bigger spheres, ellipsoids, toroids, half-fragments of all these structures, flat flakes, etc.), with allowance for amorphous hydrocarbon component and heavy impurities. It is shown that (i) wide peaks at q∼10,30 and 55nm-1 may be caused by the nanostructures formed by the curved single-layer graphene, (ii) respective most probable candidates are 2-3 nm wide, low-aspect-ratio toroids.

123Highlights►Hydrocarbon films, deposited in tokamak T-10, are diagnosed with X-ray scattering. ► Scattering curves are computed for various carbon nanostructures, using approximate approach. ► Optimization problem is solved with allowance for amorphous hydrocarbons and heavy impurities. ► It is shown that most probable candidates are 2-3 nm wide, low-aspect-ratio carbon toroids. ► Approximate approach is verified via comparison with scattering by exactly constructed toroids.