Development of r.f. powered helium glow-discharge optical emission spectrometry associated with sampling by laser ablation

In order to improve the precision of depth profiling in glow-discharge opti cal emission spectrometry, sampling from the sample electrode with laser ab lation and excitation of the sample atoms with an r.f. helium glow plasma h ave been attempted for a glow- discharge emission source. Consequently, it: has been found that sample atoms can be introduced into the glow plasma by laser ablation, and excitation of the atoms with the r.f. helium glow plas ma is possible during a period of between 100 mus and 7 ms after the irradi ation of a Q-switched Nd : YAG laser. Since the r.f. helium glow plasma has little sputtering ability, the sampling and the excitation processes can b e controlled independently; thus, the above-mentioned procedure would impro ve the precision of depth profiling in glow-discharge optical emission spec trometry. In addition, an enhancement of the emission intensity and die pro duction of metastable helium atoms were observed by using a bias-current co nducting method described in our previous paper. These effects could also i mprove the sensitivity in glow-discharge optical emission spectrometry.