Raether limit
The Raether limit is the physical limiting value of the multiplication factor or gas gain in an ionization avalanche process.
Even though, theoretically, it seems as if can increase without limit, physically, it is limited to about or .
Heinz Raether postulated that this was due to the effect of the space charge on the electric field.
The multiplication factor or gas gain is of fundamental importance for the operation of the proportional counter and Geiger counter ionizing radiation detectors.