SPECTROSCOPIC STUDIES OF MICROWAVE-PULSE-EXCITED He-Kr** plus ION LASER.

The intensity of He(I) lines in pure He discharge and some Kr(II) lines in He-Kr discharge drops rapidly at the termination of the excitation pulse and reaches a maximum after this rapid drop and then decreases slowly. The maximum intensities for the He(I) and the Kr(II) appear within at most 1 and 2 mu sec in the afterglow, respectively. The excitation of the upper levels of these lines is related to the He metastable atoms. The time dependence of the relative density of the He(2s**3S) metastable atoms in the afterglow plasma of pure He discharge is obtained from the waveform of the side light of the 388. 9 nm line. It is concluded that the density increases rapidly up to a maximum within about 1. 5 mu sec after the termination of the excitation pulse.