ABSOLUTE COPPER ATOM DENSITY DETERMINATION IN LASER-ABLATED COPPER PLASMAS USING HOOK SPECTROSCOPY

Hook spectroscopy has been implemented to measure the absolute density of atomic species in a laser-ablated plasma plume. We use the hook method to determine the density of copper atoms produced by ablation of a copper target in 25 Torr of helium at power densities of approximately 1 GW/cm2. The measured copper densities when ablating into 25 Torr of helium backing gas range from 1.5 X 10(15) CM-3 at a delay of 200 mus to 4.4 X 10(13) CM-3 at 5 ms delay. This dramatic decrease in density is due to condensation of the metal vapor to form fine particulate.