X-Ray Spectroscopy: An Experimental Technique to Measure Charge State Distribution Right at the Ion-Solid Interaction

TL;DR

This study employs x-ray spectroscopy to accurately measure charge state distributions of ions in ion-solid interactions, revealing Lorentzian behavior and highlighting discrepancies with empirical models, especially at lower energies.

Contribution

It introduces a novel x-ray spectroscopy method for measuring charge states at the interaction zone, providing insights into distribution shapes and validating predictions against models.

Findings

Charge state distributions follow Lorentzian profiles.

X-ray measurements yield higher mean charge states than empirical models.

ETACHA predictions align with experiments at energies ≥ 2 MeV/u.

Abstract

Charge state distributions of $^{56}$Fe and $^{58}$Ni projectile ions passing through thin carbon foils have been studied in the energy range of 1.44 - 2.69 MeV/u using a novel method from the x-ray spectroscopy technique. Interestingly the charge state distribution in the bulk show Lorentzian behavior instead of usual Gaussian distribution. Further, different parameters of charge state distribution like mean charge state, distribution width and asymmetric parameter are determined and compared with the empirical calculations and ETACHA predictions. It is found that the x-ray measurement technique is appropriate to determine the mean charge state right at the interaction zone or in the bulk. Interestingly, empirical formalism predicts much lower projectile mean charge states compare to x-ray measurements which clearly indicate multi-electron capture from the target surface. The ETACHA predictions and experimental results are found to be comparable for energies $\geq$ 2 MeV/u.