Evaluation of excited nl-state distributions of fast exit ions after penetrating through solid foils. Part 2: Determination of the nl-state distribution fractions of exit ions

Abstract

In Part 1 [T. Miyoshi, K. Noda, Y. Sato, H. Tawara, I.Yu. Tolstikhina, V.P. Shevelko, Nucl. Instr. and Meth. B, this issue] of our two reports, new experimental data on charge-state evolution Fq(D) and equilibrium fractions Fq∞ were presented when 4.3MeV/u projectile ions with the atomic number Z=6–26 pass through carbon. Also, in this paper, a ten-charge-state model for equilibrium fractions Fq∞ expressed in terms of the charge-changing cross sections was suggested.In the present work (Part 2), a new method is suggested to determine the nl-distributions Nq(nl) of exit ions with a charge q in the specific nl-states by solving the balance equations with all appropriate effective cross sections as coefficients. The Fq∞ and Nq(nl) values are normalized so that ∑qFq∞=1 and ∑nlNq(nl)=Fq∞. The efficiency of the present method suggested is illustrated by example of Ar ions colliding with a carbon foil at projectile energy of E=6.0MeV/u. It is found that the exit argon beam comprises about 12% of argon ions in the excited states. This method can be used for evaluation of the excited-ion components in the exit ion beam when the charge equilibrium has been reached.Besides, in this work, extending the method described in [Miyoshi et al., this issue], evaluation of nl-state distributions of exit ions at energies E=4–20MeV/u is performed for the case of Ar+C foil collisions, therefore, allowing to observe the nl-state distributions in a wide energy range.