Ein elektronisch gesteuerter Funkengenerator mit Laufzeitkettenentladung für folgefrequenzen bis 3000 Hz—I: Aufbau und arbeitsweise des generators—einige physikalische messungen

Abstract

The current flow pattern in a single spark and the repetition rate are of equal importance for quantitative spark spectroscopic analysis. For investigating these two factors separately an electronically controlled spark source was designed so that the single spark conditions and the repetition are independent of each other. Two delay lines are used as an energy storage device. They are connected in parallel for charging and in series for discharging. Charging in a resonant LC-circuit with a hydrogen thyratron as switch has the advantage of little loss while the voltage is doubled. Repetition rates up to 3000 Hz are attained at an average electric power of 2 kW. Spectroscopic measurements with copper electrodes show that with delay lines of low impedance a reasonable emission of Cu III Unes occurs. The ignition voltage, measured with an oscilloscope, decreases as the repetition rate is increased. It is shown that this is due to heating of the electrodes. The time constant of this heating process is about one minute. Detailed spectroscopic research work with this generator is being carried out at the moment. Thereby special attention is given to the questions of reproducibility as a basis for spectrum analysis and of the temporal variation of the emission. The results will be published as Part II of this paper.