An apparatus has been developed for the study of the afterglow of a rare-earth spark with a time resolution of 0.1 µsec. A hydrogen thyratron controls a rapidly firing spark gap and the spectrum of the afterglow is recorded with pulsed photomultipliers and ratio techniques. Tests with preseodymium have shown that it is possible to separate lines according to the ion of origin for the second, third, and fourth spectra, according to configuration of origin in the third spectrum of praseodymium, for example, the emission lines of the 4ƒ26p-4ƒ26s and 4ƒ25d-4ƒ3 transitions. In the case of the 4ƒ25d-4ƒ3 transition, some terms of the 4ƒ25d configuration are indicated from the more intense lines. The methods developed with praseodymium have been applied to neodymium, and some preliminary results are reported.
W. A. Hovis, JR., "Time-Resolved Spectra of Rare-Earth Ions," J. Opt. Soc. Am. 52, 649-651 (1962)