Apparatus for Time- and Wavelength-Resolved Spectroscopy

An apparatus that includes a pulsed electron gun and a high-resolution ultraviolet spectrometer has been developed for use in (1) pulsed electron-impact excitation of transitions among the electron-energy states in a gas and (2) measurement of the spectrum of the resulting ultraviolet light emitted by the gas, as a function of wavelength and of time after turn-off of the excitation. The apparatus is designed especially for measuring the Lyman-band emission spectrum of H2, in order to determine the cascade contribution to this spectrum and thereby to contribute to the understanding of cascade contributions to electron-excited spectra of gases in general.