The drift velocities of electrons in krypton, xenon, deuterium, carbon monoxide, carbon dioxide, water vapor, nitrous oxide, and ammonia have been measured for $\frac{E}{p}$ values between 2.5×${10}^{-4\mathrm{}}$ and 30 v/cm-mm Hg at temperatures between 77 and 443°K. The data were obtained from measurements of electron transit times in a double-shutter drift tube. Values of the momentum transfer cross section as a function of electron energy for electrons with energies between about 0.003 and 0.08 eV are obtained which are consistent with the measured drift velocities for thermal electrons in all the gases reported.

• Received 7 May 1962

DOI:https://doi.org/10.1103/PhysRev.127.2084