The time‐of‐flight (TOF) method for the determination of electron‐diffusion coefficients D and drift velocities w described earlier could not be used to investigate a number of gases because a Gieger—Müller counter was used for an electron detector. A new experimental apparatus using differential pumping and an electron‐multiplier detector was developed to remove this restriction. Using this new apparatus, D and w have been measured for He, Ar, H2, N2, CO, CO2, CH4, and C2H4. Considerable divergence of D values from published values by the Townsend method have been obtained, indicating a fundamental difference in the methods.
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© 1967 American Institute of Physics.
1967
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