Manifestation of the Penning effect in gas proportional counters

Penning transfer has significant influence on electron avalanche growth in mixtures in which the ionization potential of quenching agent is below excitation levels of the main gas. The influence of the Penning effect on gas gain factor, effective ionisation potential and on ɑ/p as the function of admixture concentration (from spectroscopically pure main gas up to few percentage of admixture) is shown for Ar and Kr based working gas with cyclohexane, ethanol, isopentane and CO2 as the quenchers.