Average charge states of heavy and superheavy ions passing through a rarified gas: Theory and experiment

J. Khuyagbaatar*, V. P. Shevelko, A. Borschevsky, Ch. E. Duellmann, I. Yu. Tolstikhina, A. Yakushev

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

The average charge states (q) over bar of heavy and superheavy ions (atomic numbers Z = 80-114) passing through He gas are studied experimentally and theoretically. Experimental data were measured at the gas-filled recoil separator, i.e., the TransActinide Separator and Chemistry Apparatus (TASCA) at GSI Darmstadt, for ion energies of a few hundred keV/u at gas pressures of 0.2 to 2.0 mbar. An attempt is made to describe experimental (q) over bar values by means of atomic calculations of the binding energies and electron-loss and electron-capture cross sections. The influence of the gas-density effect is included in the calculations. The calculated (q) over bar reproduce the experimental values for elements with Z = 80-114 within 20%. A comparison with different semiempirical models is presented as well, including a local fit of high accuracy, which is often used in superheavy-element experiments to estimate the average charge states of heavy ions, e.g., at the gas-filled recoil separator TASCA. The (q) over bar values for elements with Z = 115, 117, 119, and 120 at He-gas pressure of 0.8 mbar are predicted.

Original languageEnglish
Article number042703
Number of pages8
JournalPhysical Review A
Volume88
Issue number4
DOIs
Publication statusPublished - 8-Oct-2013
Externally publishedYes

Keywords

  • CHANGING CROSS-SECTIONS
  • CA-48-INDUCED REACTIONS
  • IONIZATION-POTENTIALS
  • ELECTRONIC-STRUCTURE
  • HEAVIEST ELEMENTS
  • EXCITED-LEVELS
  • SEPARATOR
  • EXCITATION
  • DISCOVERY
  • ENERGIES

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