Abstract
Emission characteristics of the laser ablation–hollow cathode helium glow discharge source were examined. It was found that one of the major excitation mechanisms of atomic emission lines having excitation energies of around 3 eV is collisions of electrons with analyte atoms, and that the collisions between sample atoms and metastable helium atoms in the glow discharge plasma play an important role in the excitation of emission lines having excitation energies larger than 4 eV. Emission peaks of atomic helium and carbon contaminants were sufficiently suppressed by the present method, i.e. simply subtracting the emission spectrum with glow discharge alone from the spectrum with both glow discharge and laser ablation. Since it is possible to distinguish between atomic emission spectrum of carbon contained in a steel sample and the spectrum of carbon contaminants in the plasma gas, the response time for the analysis of carbon will be shortened using the present method.
