The Drift Velocity of Electrons in Oxygen at 293 K

Abstract

The drift velocity of electrons in oxygen at 293 K has been measured over the range 0.8 ≤ E/N ≤ 12 Td by the Bradbury–Nielsen time-of-flight method. The factors governing the range over which measurements can be made are discussed and it is shown that long drift tubes should be used for drift velocity measurements in oxygen at low values of E/N. A 50 cm drift tube is described. The error in the present results is estimated to be less than 1 % for 1.8 E/N E/N > 6 Td and at 1.5 Td, 5 % at 1 Td, and 10 % at 0.8 Td. The present data are in good agreement with those of Fleming et al. (1972) and Nelson and Davis (1972) over the E/N range where the sets of data overlap.