The Structure of a Stream of Electrons and Ions Drifting and Diffusing in a Gas When Ionization by Collision and Molecular Attachment are Present

SummaryExperimental results are given for the ratio W xl W. of transverse to longitudinal drift velocity for electron swarms in nitrogen moving in crossed electric and magnetic fields. The results, obtained by Huxley's method, cover the range 0·04 < Elp < 8·0V cm-1 torr-1 at 293°K. The apparatus and experimental procedures which have been developed permit accurate measurements to be made so that significant tests of the method have been possible over wide ranges of the experimental parameters. Information concerning the variation of the momentum transfer cross section with electron energy, and concerning the energy distribution function, can be obtained by comparing a quantity WM = (EIB) (WxIW.) with the true drift velocity W. The results of this comparison are discussed in relation to recent theoretical analyses.

Section: (D) Theory Of the Methods Of Measuring Wx/w Zmentioning

confidence: 99%

Transport Coefficients for Low Energy Electrons in Crossed Electric and Magnetic Fields

Jory¹

1965

“…It has been shown by Huxley (1959) that in the case of a stream of electrons diffusing through a gas in which both ionization and attachment processes are occurring, the ratio R of the current received by the annulus A2 to the sum of the currents received by the annuli A2 and A3 is given by…”

Section: Methodsmentioning

confidence: 99%

Measurements of Townsend's Energy Factor k1 for Electrons in Carbon Dioxide

Rees¹

1964

SummaryValues of Townsend's energy factor kl for electrons in carbon dioxide have been determined as a function of the parameter E/p for 0·1 .;;; E/p .;;; 50 at a temperature of 293°K. The results are compared with those of other investigators and are used in a recomparison of the cross sections for electron attachment deduced from swarm and beam types of experiments for swarms of electrons having mean energies of up to 5 eV.

“…The difference between the two sets of terms is not simple but involves at least one order of p. This means that for sufficiently low p, secondary emission is unimportant and (S3) reduces to (91) It follows that (92) this leading to the Huxley-Crompton relationship with, however, ,\' replacing A. This result was originally derived by Huxley (1959).…”

Section: C(g)-d(g)mentioning

confidence: 80%

A Theoretical Analysis of the Townsend - Huxley Swarm Technique for Electrons

Hurst¹,

Liley²

1965

SummaryThe Townsend-Huxley swarm technique for electrons is analysed in detail. Particular emphasis is placed on boundary conditions, and those conditions appro· priate to the Huxley-Crompton empirical relationship are derived and explained. Secondary emission at the electrodes due to both positive ion and photon bombardment is also taken into account. The principal result is an integral expression for the current ratio received at the circumferentially split anode. From this may be deduced the energy factor kl and the secondary emission coefficients. It is shown that it is possible to distinguish between positive ion and photon secondary emission and to determine the associated coefficients simultaneously in the stationary state. Highly accurate conditions for electrical breakdown are also obtained, secondary emission at the anode being taken into account.