Gas multiplication process in high pressure proportional counters

Gas multiplication process in high pressure proportional counters S. Koperny, T. Z. Kowalski AGH University of Science and Technology Al. Mickiewicza 30, 30 -059 Kraków, Poland Gas gain as function of applied high voltage for Ar + 20%CO 2 (left) and for Ar + 6. 4%CO 2 + 2, 5%N 2 (right). The gas value of the amplification factor was determined using the current method as the ratio of the current value at given high voltage to the current value in the ionization chamber mode. The same as above in notation proposed by Zastawny as ln. A/(p*r *Sa). In this parametrisation, gas gain function is of unique reduced electrical field strength at the anode surface, Sa. Gas gain in coordinates proposed by Williams & Sara, for selected and all measurements. Straight line dependence indicate on aplicability of this formula and allows to determine α/p. Results: - gas gain as high as 105 can be reached, - the formula of Williams & Sara can be used to describe the gas gain in studied mixtures in wide range of working gas pressure and counter dimensions, - the first Townsend coefficient, which is still the First Townsend coefficient as a function of reduced electrical field. main parameter describing the physical processes accuring in the gas mixtures has been determined as a function of electrical field.