Axial view of an inductively coupled plasma

Lateral, or side-on, viewing is the accepted viewing configuration of spectrometers used for inductively coupled plasma atomic-emission spectroscopy (ICP-AES). For side-on viewing extensive studies have been carried out to elucidate the spatial power and injector flow-rate dependences of element emission intensities in the plasma in the so-called hard and soft line regions of the plasma. In this study a viewing configuration in which the plasma is orientated horizontally to the spectrometer rather than vertically has been used. Thus, the viewing is axial. The spatial dependence of ion and atom line ratios of calcium and signal to background ratios have been evaluated and the electron density, ionisation temperature and excitation temperature measured using this optical arrangement.