Abstract
The concentration effect of the reactant gases, Ne, N2, Ar and Kr, admixed with the helium gas is studied in the injected-ion drift tube by comparing the mass spectra of the reservoir gas and of the gas sampled directly from the drift tube. It is found that the flow through the aperture of the drift tube, which has a diameter of 0.7 mm ∅, is “medium flow” in the present experimental pressure range(from 0.2 to 1.4 Torr), and that the concentration ratios vary with the pressure in the drift tube. The concentration ratios measured at 0.6 Torr which is most frequently used are 1.8, 2.15, 2.32 and 3.0 for the case of Ne, N2, Ar and Kr, respectively. These results are compared with the theory of the two component gas flow through an aperture. The correction of reaction cross sections previously measured by the injected-ion drift tube technique is described. The correction factor for the charge transfer cross section 22Ne++ 20Ne → 22Ne + 20Ne+ is found to be 0.89, and more satisfactory agreement with theory is obtained.
