Empirical relationships for heavy-ion equilibrated charges and charge-changing cross-sections in rarefied hydrogen and their application

TL;DR

This paper investigates the charge state distributions of heavy ion residues in gas-filled separators, providing empirical relationships for charge-changing cross-sections to improve trajectory simulations in nuclear physics experiments.

Contribution

It offers new empirical formulas for charge-changing cross-sections of heavy ions in hydrogen, aiding accurate modeling of ion charge evolution in gas-filled environments.

Findings

Derived empirical relationships for charge-changing cross-sections.

Validated the formulas with experimental data.

Enhanced accuracy of ion trajectory simulations.

Abstract

Highly ionized heavy evaporation residues (ERs) resulting from heavy ion (HI) fusion-evaporation reactions are knocked out from solid targets to rarefied gas of gas-filled recoil separators. In gas, these ERs undergo charge-changing collisions on their way to a detection system. An equilibrium between the loss of charge (electron capture) and the gain of charge (electron loss) for ionized ERs allows one to use equilibrated charge state distributions in trajectory calculations for ERs moving through a magnetic field. The distance from a target to the point where the ER charge state distributions become to be the equilibrated one is essential for such calculations. This distance can be estimated in simulations based on electron capture and loss cross-sections for energetic HIs. Proper approximations of available experimental data have provided these cross-sections, which were applied to the simulation of the ionic charge evolution for ionized heavy ERs.