Equilibrium Charge Distribution Of Ions Research Articles

Empirical method evaluation of charge – Changing cross sections

A method based on experimental data, theoretical models, and the empirical estimation of experimental parameters in the equilibrium charge distribution of ions is proposed to evaluate charge changing cross sections. This method makes it possible to obtain cross sections for loss and capture of one or several electrons in gaseous and solid targets with the inclusion of the influence of excited states of ions and target atoms.

Effect of the capture and loss of two electrons on the charge distributions of ions

The effect of the processes of capture and loss of two electrons on the width of the equilibrium charge distribution of ions in different materials is studied. These processes increase the width of the equilibrium charge distribution in the energy region of E < 0.1 MeV/nucleon. The effect increases with decreasing ion nuclear charge and reaches 10–15% for boron ions.

Equilibrium thickness of carbon target interacting with nitrogen and neon ion beams

The method for calculation of the target thickness which is required for the formation of equilibrium charge distribution of ions is proposed. The description of nonequilibrium processes is based on empirical estimations of charge-exchange cross sections, taking the density effect for solids into account. The variation of the average charge and the width of the nonequilibrium charge distribution as a function of the target thickness is analyzed. The results of calculations for nitrogen and neon ions in carbon are compared with experimental data.

Methods of estimation of equilibrium charge distribution of ions in solid and gaseous media

Abstract The new version of theoretical estimation of equilibrium charge distribution of ions passing through the matter is proposed. This estimation is based on the correction of charge exchange cross sections for gases taking into account the density effect. The results of calculations are compared with experimental data and with empirical estimation based on the averaging of experimental data for charge distributions of ions in gases and solids. The theoretical method describes the experimental oscillations of width of the charge distribution in contrast to the empirical method.

Charge distribution of nitrogen ions reflected from copper and graphite surfaces

A method for the theoretical estimation of the equilibrium charge distribution of ions passed through a media is proposed. It is based on the correction of charge-exchange cross sections for gases using a factor taking the density effect into account. The calculated charge distribution of N ions in graphite agrees well with the existing experimental data. This method makes it possible to estimate the charge distribution of fast N ions reflected from a Cu surface.

Empirical estimation of the equilibrium charge distribution of heavy ions in solid and gaseous media

Abstract Based on the analysis of experimental data on equilibrium charge distributions of ions in gases and solid media, the analytical parameterization of the charge distribution width as a function of the average ion charge and nuclear charges of the ion and the target atom and that of the asymmetry as a function of the average ion charge are obtained. The proposed relations are applicable in a broad energy interval and describe the existing experimental data satisfactorily.

Systematics of equilibrium charge distributions of ions passing through a carbon foil over the ranges Z=4-92 and E=0.02-6 MeV/u.

Equilibrium charge distributions have been measured for 18 kinds of ions passing through a carbon foil in the energy region of 1\char21{}6 MeV/u for light ions and of 0.2\char21{}1 MeV/u for heavy ions. By combining the data obtained at present with those reported for other energies or ion species, an attempt is made to find the systematics for charge fraction F(q), mean charge q\ifmmode\bar\else\textasciimacron\fi{}, and distribution width d over the wide range of ion species Z and energy E. Strong correlation has been found between the shell structure of ions and the variation of q\ifmmode\bar\else\textasciimacron\fi{} or d with Z or E. The analysis for this correlation enables the evaluation of rather reliable values of q\ifmmode\bar\else\textasciimacron\fi{}, d, or F(q) for ion species 4\ensuremath{\le}Z\ensuremath{\le}92 in carbon foils from 0.02 to 6 MeV/u.

Projectile atomic number dependence of equilibrium charge states for 1 and 2 MeV/u ions passing through a carbon foil

Equilibrium charge distributions of ions after passage through a carbon foil have been measured for various ions at 1 and 2 MeV/u. Mean charges, q , compared at 1 MeV/u show an enhancement at around Z 1 = 29. The shell effect of the charge distributions is closely related to this enhancement of q .