Light radiated from transient spark discharges varies with time as the conditions vary in the source. Observation of the variation with time of the radiation emitted gives useful information concerning excitation levels, intensity variation, intensity ratios, pressure broadening, wavelength shift, Stark broadening, and self absorption of spectrum lines. This information can be obtained from time-resolved spark spectra taken with an electronically controlled high precision spark source, combined with a rotating mirror optical system. From time-resolved spark spectra, spectrum lines suitable for spectrochemical analysis can be selected on a theoretical basis. In time-resolved spectra the continuous background originating at the beginning of the discharge is separated from the rest of the spectrum. The background-free spectrum, in addition to facilitating the construction of straight working curves without background correction, is suitable for estimation of minor constituents in metals and alloys. The background separated from the rest of the spectrum can be used as an internal standard in spectrochemical analysis. As an example, working curves are given for the estimation of impurities in aluminum.
A. Bardocz, "Time-Resolved Spectroscopy in Spectrochemical Analysis," Appl. Spectrosc. 11, 167-173 (1957)