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The possibility of direct experimental evaluation of the ionisation rates pertinent to a given excitation scheme of atomic species in an air-acetylene flame is reported. The method relies on the observation of the rise time of the current pulse induced on the electrode by the negative charge created in the ionisation process. The signal collected on the burner, after amplification by a 300 MHz preamplifier, is analysed by a fast digital storage scope. The resolution is limited on one side by the response time of the preamplifier used and on the other side by the duration of the laser pulse, which then restricts the range of measurable rates to one order of magnitude. The method is applied to the determination of the effective ionisation rate of the sodium 4d levels reached in a two-step excitation scheme via the 3p levels. Care was taken to avoid space charge effects in the flame. Under saturation, the measured values vary from 0.27 to 3.4 GHz.

Additional information

Authors: MATVEEV O I, JRC Ispra (IT);OMENETTO N, JRC Ispra (IT)
Bibliographic Reference: Article: Spectrochimica Acta, Vol. 49B (1994) No. 7, pp. 691-702
Record Number: 199411442 / Last updated on: 1994-12-06
Original language: en
Available languages: en
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