On the Swarm Method for Determining the Ratio of Electron Drift Velocity to Diffusion Coefficient

Abstract

The use of data from swarm experiments for electron energies approaching those corresponding to thermal equilibrium demands results of greater precision than has hitherto been available. In order to examine the possibility of producing such data, the swarm method for detennining W / D has been extensively examined over a range of values of the parameter E / p where the agreement between the results of recent investigations is not good. A number of factors influencing the accuracy of measurements of this type are discussed. The results for hydrogen which are presented are considered to be subject to an error of less than 1 %.