Systematics of equilibrium charge distributions of ions passing through a carbon foil over the rangesZ=4–92 andE=0.02–6 MeV/u

Abstract

Equilibrium charge distributions have been measured for 18 kinds of ions passing through a carbon foil in the energy region of 1 -6 MeV/u for light ions and of 0.2 -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, 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 or d with Z or E. The analysis for this correlation enables the evaluation of rather reliable values of q, d, or F(q) for ion species 4~Z~9 2 in carbon foils from 0.02 to 6 MeV/u.

Electronic Sputtering of Thin Conductors by Neutralization of Slow Highly Charged Ions

“…Resulting average transmitted ion charge states range from 0 for O 71 to 11 for Ar 181 and 1.61 for Th 701 ions. These values agree with measurements and calculations of mean equilibrium charge states of ions at similar velocities [22]. We observed a reduction in average charge states after passage through two stacked 10 nm thick carbon foils from 1.11 to 0.71 for Kr 331 and from 1.61 to 1.11 for Th 651 and attribute this to the continuous slowdown of ions in the foils, and to the decay of any excited states left after transmission of the first foil.…”

Charge state distribution ofKr86in hydrogen and helium gas charge strippers at2.7 MeV/nucleo

“…The electron traveling with projectile with kinetic energy of 2.7 MeV=nucleon (β ¼ 0.076) has a kinetic energy of 1.5 keV. It is difficult to strip electrons with removal energies higher than 1.5 keV [47,48]. This fact also implies that excited states have little contribution in ionization process in gases [45].…”

Equilibrium and non-equilibrium charge-state distributions of 2.0MeV/u carbon ions passing through carbon foils

“…Both simulations also succeeded in qualitatively emulating such overshooting behavior of charge-distribution widths for C 2+ , C 3+ , C 4+ , and C 5+ ion injections as well as the monotonous increase of that for C 6+ ion injection in Table 1 Equilibrium charge-state distributions FeqðqÞ for outgoing C q+ ion fractions (q = 3-6), mean charge-states qeq, charge-distribution widths d eq , and skewness s eq for 2.0 MeV/u C-ions through C-foils. Top two lines, nine lines in the middle, and bottom two lines show experimental results, values given by (semi-)empirical formulae [4,5,[7][8][9][10][11][12][13][14], and simulation results, respectively. The equilibrium foil-thickness was estimated to be 10 lg/cm 2 in the present experiment.…”

“…Following injection into matter, fast heavy ions change their charge states until they establish charge equilibrium, in which increases and decreases in population of each charge-state balance each other, and the population seems to remain unchanged [1]. Representing an important part of atomic collision physics, many papers have been devoted to equilibrium charge fractions, mean charge states, widths, and the skewness of the distribution, which have been compiled in past reviews [2][3][4][5][6]. Also, empirical and semi-empirical formulae to predict the equilibrium mean charge states, distribution widths, and skewness have been presented [7][8][9][10][11][12][13][14].…”

“…Regarding the C q in + + C collision system, several experiments were carried out after a compilation of papers published up to 1989 [2][3][4], including Sato et al and Miyoshi et al from the same group, who studied equilibrium and non-equilibrium charge-state distributions at 4.3, 6.0, and 2.65 MeV/u [22][23][24][25], and Schmitt et al, who reported equilibrium charge-state distributions at 3-6 MeV [26][27][28]. Baudinet-Robinet and Dumont studied relative population in sub-shells as well as charge fractions of C + , C 2+ , and C 3+ ions between 0.3 and 2.3 MeV by beam-foil experiments [29].…”