Electron Drift Velocity In Gases Research Articles

A simple method for measuring electron drift velocity in gases using grid ionization chamber

A simple method for measuring the electron drift velocity in gases with a given electric field using a grid ionization chamber is proposed and demonstrated. By collimating incident α particles that are perpendicular to the electric field, the drift velocity can be derived easily using the electron drift distance from primary ionization to a grid divided by the time interval between the cathode and anode signal starting times. These experimental settings can avoid additional signal processing of signals and reduce the effect of electron diffusion. Using this method, the measurement of electron drift velocities in 90% Ar + 10% CO2 is presented. Measured results agree well with the simulated values and with existing experimental results.

Rf breakdown of low-pressure gas and a novel method for determination of electron-drift velocities in gases

This paper reports the results of the detailed and comprehensive experimental and theoretical treatment of the rf gas breakdown. We give the measured breakdown curves of the low-pressure rf discharge in argon, hydrogen and air in a broad range of gas pressures and interelectrode distances. The different processes of generation and loss of charged particles participating in the rf gas breakdown are discussed. We suggest to distinguish the following sections on the rf discharge breakdown curves: multi-pactor, Paschen, diffusion-drift and emission-free ones. The analytic gas breakdown criterion of the combined (rf plus weak dc electric field) discharge taking into account the anisotropy of electron diffusion in the electric field is obtained. A novel method for determining the electron-drift velocity from the measured rf breakdown curves is suggested. The electron-drift velocity data in argon, hydrogen and air obtained with this technique in the range -2000 V are given and compared with those got by conventional means.

A New Method for Electron Drift Velocity Measurement Using Frequency Response Analysis

A simple method for the measurement of electron drift velocity in gases under electric fields is presented. In this method, sinusoidally modulated electron current through the drift space is measured with a lock-in amplifier in place of using two shutters. The phase delay of the electron current referred to the electron release rate from the cathode gives an accurate mean transit time of electrons through the drift distance between the cathode and anode. The results of preliminary measurements of the electron drift velocity in argon are in good agreement with formerly reported data. In spite of simple procedures, this method will be useful for accurate measurements of electron drift velocity in various gases over wide ranges of the reduced electric field.

Evaluation of the real space electron drift velocity in gases using moment equations performed in velocity space

The centroid drift velocity and the mean electron velocity of electron swarms in gases have different values even under the same electric field when electron-impact ionization and/or electron attachment processes are present. A new evaluation technique for is proposed based on moment equations, in which the quantitative difference between and is described as a function defined in velocity space. values are derived from calculations using a propagator method performed in velocity space without the electron distribution in real space. The effects of ionization and attachment on are quantitatively analysed for and , and the mechanism producing the difference between and is illustrated.

Comment on the Braglia-Dallacasa theory of the density dependence of the electron drift velocities in gases

It is shown that the formula for the drift velocity of electrons in gases presented by Braglia and Dallacasa, and also other more general formulas, can be derived from the Kubo-Greenwood relation without using Braglia and Dallacasa's assumptions about the angular distribution in the scattering and the form of the optical theorem. Several approximate drift-velocity formulas are tested numerically and compared with experimental data for the case of electrons in argon.

A highly accurate and simple expression of electron drift velocity in gases and semiconductors

The drift velocity for electrons (or holes) in a scattering medium is obtained as the sum of the usual first-order expression plus a correction term. Both terms are expressed as integrals over a single variable and the integrands are known functions of the electron differential collision frequency. Since the correction term is small compared with the principal, usual term, the expression obtained is in practice equivalent to an explicit rigorous solution.

Theory of the density dependence of electron drift velocity in gases

Theory of the density dependence of electron drift velocity in gases

Single site scattering and drift velocity of electrons in gases

The results of a t matrix formulation are used to discuss the pressure dependence of electron drift velocity in gases.

Resonance Scattering and the Drift Motion of Electrons through Gases. II

In a previous paper, recent observations of pressure-dependent electron drift velocities in gases were interpreted in terms of new ${\mathrm{H}}_{2}^{\ensuremath{-}}$ or ${\mathrm{N}}_{2}^{\ensuremath{-}}$ temporary ion states. In this paper, it is pointed out that both the lifetime $\ensuremath{\tau}$ of the ion state and the mean electron-molecule collision frequency for trapping collisions can be obtained from experiment. The existing data are shown to yield an upper limit of $\ensuremath{\tau}\ensuremath{\le}{4.10}^{\ensuremath{-}9}$ sec for hydrogen. It is thought that much shorter lifetimes can actually be measured, and clues to this end are given.

Method for the Determination of Electron Drift Velocity in Gases from the Characteristics of High-Pressure Gas Diodes

A method has been developed for determining electron drift velocities from measured current-voltage characteristics of gas-filled cylindrical diodes. Experimental data, taken in diodes filled with helium, nitrogen, and argon, are presented to illustrate the utility of the method.