Laser Generation of Particles to Simulate Aerosols from Fusion Systems

A pulsed Nd:YAG laser is being used to aerosolize material from the surface of metal targets to simulate particles created in fusion energy systems. Targets in the form of rods up to 2-cm diameter can be attached to a screw mechanism that exposes a fresh surface for each laser pulse. Energies up to 20 J/pulse can be applied to the target, at pulse rates from a single shot to 300 Hz. Energy can be focused on an area with diameter less than 500 µm. Stainless steel and aluminum targets were used in a demonstration of system performance. The branched-chain ultrafine aggregate aerosols that were produced appeared to result from direct vaporization/condensation of material from the surface of the target located under the center of the laser beam, and from ejection of molten droplets from the target surface.