Abstract: A method and apparatus for manufacturing nanoparticles by passing a carrying fluid with a nanoparticle precursor through an RF plasma volume for heating the fluid with a nanoparticle precursor to a high temperature sufficient to synthesizing the nanoparticles. The suspension of the fluid with nanoparticles is passed to the thermalization zone in a diverging portion of the Laval nozzle for subjecting the fluid with nanoparticles to jumpwise adiabatic expansion at the exit from the converging portion of the Laval nozzle to the thermalization zone. At least the diverging portion has a curvilinear profile optimized with respect to conditions of said thermalization. In the thermalization zone, the flow of fluid with nanoparticles is surrounded by a cylindrical oil shower composed of discrete drops of oil. The oil shower is emitted from a shower ring that performs twisting motions.