Method for quenching:

Proportional counters are very sensitive, and the voltages are large sufficient so in which all of the electrons are collected inside a few tenths of a microsecond. Every pulse corresponds to one gamma ray or neutron interaction. The amount of charge in every pulse is proportional to the number of actual electrons generates. The proportionality factor in this case is the gas amplification factor. A number of electrons generates are proportional to the energy of the incident particle.

For every electron collected within the chamber, there is a positively charged gas ion left over. These gas ions are heavy compare to an electron and move much more slowly. Finally the positive ions move away from the positively charged middle wire to the negatively charged wall and are neutralized through gaining an electron. Within the procedure, few energy is provided off, that causes further ionization of the gas atoms.  An electron generates through this ionization move toward the middle wire and is multiplied en route. This pulse of charge is not related to the radiation to be detected and could set off a series of pulses.  These pulses have be eliminated or "quenched."

One method for quenching these discharges is to add a small amount ( 10 percent) of an organic gas, like as methane, in the chamber.  A quenching gas molecule has a weaker affinity for electrons than the chamber gas does; thus, the ionized atoms of the chamber gas readily take electrons from the quenching gas molecules. Therefore, the ionized molecules of quenching gas reach the chamber wall alternatively of the chamber gas. The ionized molecules of the quenching gas are neutralized through gaining an electron, and the energy liberated does not cause additional ionization, other than cause's dissociation of the molecule. That dissociation quenches multiple discharges. A quenching gas molecule is eventually consumed, therefore limiting the lifetime of the proportional counter. There are, therefore, a few proportional counters which have an indefinite lifetime since the quenching gas is constantly replenished. Those counters are referred to as gas flow counters.