The primary specific ionization in gases of positrons and electrons II

By utilizing the dependency of the efficiency of a Geiger counter upon the primary ionization of a counted particle, the mimimum primary specific ionization of electrons in several gases has been determined. The values obtained are: (1) Gas (2) ion pairs/centimeter/atmosphere Helium 5.47 ± 0.09 Neon 11.6 ± 0.4 Argon 29.8 ± 1.5 Ethylene 40.1 ± 1.0 Ethyl alcohol vapour 6l.5 ± 1.5 The dependence of specific ionization upon the energy of the primary electron has been investigated between the energies of O.158 and 0.351 MeV. The primary specific ionization of positrons and electrons of the same energy has been found to be the same to within 1%.Science, Faculty ofPhysics and Astronomy, Department ofGraduat