Ionization cross section of noble gas atoms by electron impact

The paper presents an analysis of data on the cross sections for ionization of noble gas atoms by electron impact. For the selected sets of experimental and theoretical data an analytical formula is proposed, based on separate accounting for the knockout of electrons from the outer and inner shells, and the corresponding approximation coefficients are selected. The obtained semi-empirical formula reproduces the values of the ionization cross sections in a wide range of energies with an accuracy of several percent. The analysis of the approximation coefficients makes it possible to reduce the influence of errors in the initial experimental data and significantly increase the accuracy of estimating the ionization cross sections

Analytical approximation of cross sections of collisions of electrons with atoms of inert gases

The paper presents an analysis of data on the cross sections of elastic and inelastic collisions of electrons with noble gas atoms. The transport (diffusion) cross section, the excitation and ionization cross sections are considered. The bibliography on the cross sections of electron-atomic collisions includes many thousands of works. But the critical analysis of the results of experimental data in the review work is very difficult due to the fact that the necessary initial data can only be available to the authors of the work. The errors of the order of 1-3% given in the original works are contrasted with each other, sometimes differing by 50%. Comparisons of the electron cross sections sets in noble gases was made. For the selected sets of experimental and theoretical data, optimal analytical formulas are found and approximation coefficients are selected for them. The obtained semi-empirical formulas allow us to reproduce the cross-section values for them in a wide range of collision energies from 0.001 to 10000 eV with an accuracy of several percent. Key words: electron atomic collisions, transport cross section, excitation cross section, ionization cross section, approximation of cross sections, noble gases

Alkali ions mobility in parent vapor

Сеrtain approximations of mobility coefficients for the metal atoms’ ions in parent vapor are investigated, a comparison between experimental data was drawn, and Monte Carlo calculations are performed. In contrast to ions of noble gases, ions and atoms of alkali metals have a number of features that must be considered when building a model of ion-atom collisions. Approximations for mobility coefficients for the alkali ions in parent vapor are given, they are valid not only in the weak electric field limit, but also in strong fields, when ion heating enacts in external electric field. On the basis of the analysis of Monte Carlo calculations and comparing them with experimental data on the mobility of alkali metal ions in noble gases, we obtain approximation formulas for the mobility of alkali metal ions in parent vapors. The parameters found earlier for the approximation of the drift velocity of ions of noble gases are also given as a reference material. The parameters obtained in this work for the approximation of the mobility of alkali metal ions in parent vapors can be used to estimate the characteristics of a gas-discharge plasma

Calculation of ionization and runaway electrons characteristics in helium with iron vapor

On the basis of the Monte Carlo method and the many particles dynamics, the ionization and drift characteristics of electrons in a constant field drifting in helium with a certain amount of iron vapor are calculated. The main attention is paid to the study of the influence of iron vapor concentration on the characteristics of escaping electrons. The formulation of the problem involves the death of electrons on the wall and the balance between the birth of ionization and leaving the escape mode (whiz). The obtained results indicate a sharp change in the ionization characteristics when an easily ionizable additive in the form of iron vapor is added to helium. Starting with a fraction of a percent of the concentration of iron atoms in helium, due to the strong ionization of iron atoms, there is a strong change in the electron distribution function, which leads to a significant increase in the frequency of ionization and a nonmonotonic dependence of the number of escaping electrons on the concentration of iron vapors.