Über die Wahrscheinlichkeit der „Kanalbildung“ aus einer großen Elektronenlawine

Abstract

Investigations on avalanches of large carrier numbers (>10⁸) show the following characteristic features of the streamer mechanism, known as „Kanal-Aufbau“.

• 1. An avalanche can only start a streamer, if the carrier number of the avalanche has reached a certain critical valuen _krit. Having surpassedn _krit the probability of this streamer formation increases monotonously with growing carrier number. The applied field E₀ is kept constant.

• 2. The probability of streamer formation for a constant carrier number of the avalanche increases with the applied field. The critical carrier number can therefore be reduced by increasing the applied field.

• 3. As a consequence of this behaviour of individual avalanches the mean probability of an electron running through the gap to start a streamer increases if the mean value of amplification (e ^αd) becomes higher or (what is in this case identical) the applied field is increased. There is a critical mean value of amplification, below which it is impossible to observe any streamer formation.

• 4. If the carrier number of an avalanche reachesn≅ 10⁸ a process comes into force which is characterized by an increase of ionisation.