抄録
The effects of seeding and mass separation in molecular beams of helium and argon binary mixtures are experimentally studied to quantitatively handle composition fraction deviations which inevitable occur during transport from the gas source chamber to the detecting instrument. The experiment is carried out over the source molar fractions χ0=0∼100% and the source pressure p0=25∼75 Torr under a constant room temperature. Heavier argon molecules are remarkably accelerated by the seeding effect due to lighter helium ones, especially at χ0<1%, and the translational kinetic energy gain ratio reaches to the mass ratio of the binary molecules of 10. The Mach number of argon, however, slightly reduces. The mass separation effect is also prominent at χ0<1%, and the total species enrichment factor attains also 10. The effect is essentially due to the Mach number focusing, which is observed by the difference in spatially spread behaviors between helium and argon molecules.
