LASER-ABLATION SOLID SAMPLING - VERTICAL SPATIAL EMISSION INTENSITY PROFILES IN INDUCTIVELY-COUPLED PLASMA

Spectral emission intensity in the inductively coupled plasma (ICP) wa s measured versus height above the load coil during laser ablation sol id-sample introduction. The laser-beam pulse width, power density, and wavelength, and the sample composition are know to effect the particl e size distribution of the ablated mass. Ceramic and metal samples wer e ablated using nanosecond and picosecond pulses, and provided similar emission intensity profiles for common elements, indicating that chan ges in the particle size distribution are not manifested in the vertic al spatial emission profile. The gas environment in the ablation chamb er also influences the particle size distribution as well as the ablat ion interaction. Gas composition will influence the spatial emission i ntensity profile because of changes in the excitation characteristics of the ICP. A preliminary study using noble gases in the ablation inte raction was conducted by keeping the spatial profile constant, maintai ning a constant total gas composition to the ICP.