Electron-beam diagnostics of rarefied gases: Activation by short electron packets

The excitation of light emission of the 0-0 band of the first negative system of the nitrogen ion by activation of nitrogen molecules using short pulses of fast electrons was studied. The intensity and width of the light response were measured as functions of the duration and amplitude of the exciting current pulse and of the density of nitrogen molecules. The contribution of slow secondary electrons to the excitation of the ions increases with increase in both the gas density and the duration of the current pulse. Since the processes of excitation of ions by fast primary and slow secondary electrons are separated in time, when measuring the light-signal intensity, it is possible to determine the contribution of secondary electrons to the excitation.