Abstract :
In corona tubes, the first Townsend ionisation coefficient ¿ varies with electric field in a dependence law, which in most gases is not known analytically. The generalised secondary ionisation coefficient ¿ may be evaluated from measurements of the breakdown potential, gas pressure and using tabulated values of the primary ionisation coefficient. An expression containing an integrand, which cannot be described by analytical function, must be then solved to obtain ¿. In the letter, ¿ is evaluated using a digital computer. The computation has been carried out so far in the inert gases, mercury vapour and in an additional seven molecular and polyatomic gases.
