Simultaneous assessment of energy, charge state and angular distribution for medium energy ions interacting with ultra-thin self-supporting targets: A time-of-flight approach

R Holeňák,F Sekula,D Primetzhofer,S Lohmann

doi:10.1016/j.vacuum.2020.109988

R Holeňák, F Sekula + Show 2 more

Open Access

https://doi.org/10.1016/j.vacuum.2020.109988

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Journal: Vacuum	Publication Date: Dec 13, 2020
Citations: 12	License type: cc-by

Affiliation: Uppsala University, Brno University of Technology

Abstract

We demonstrate simultaneous measurements of the charge state, energy and angular distribution of keV ions in transmission experiments through self-supporting foils. Using a time-of-flight approach we have introduced an electrostatic deflection apparatus as an extension to existing medium energy ion scattering (MEIS) instrumentation. Different positive, neutral and negative charge states have been discriminated and quantified for initially singly charged beams of He, N, O and Ne in the energy range from 25 to 250 keV. In parallel, the ion energy after interaction with the target has been assessed for all detected particles, while particles can be discriminated by deflection angle. Self-supporting thin carbon foils were used as samples to benchmark our experiments with literature data where available.

Highlights

We demonstrate simultaneous measurements of the charge state, energy and angular distribution of keV ions in transmission experiments through self-supporting foils
The energy deposition by keV ions in materials is of ultimate importance for materials modification processes, ranging from space weathering over sputter deposition to ion implantation [1,2,3]
The observed energy deposition into the electronic structure of the target material is caused by a number of inelastic interactions: Apart from direct excitations in binary collisions, the charge state of the projectile can fluctuate as a consequence of electron loss and capture in close collisions with the target atoms

Summary

Introduction

We demonstrate simultaneous measurements of the charge state, energy and angular distribution of keV ions in transmission experiments through self-supporting foils. The most extensive experimental work on charge fractions was performed using carbon foils. An extensive contribution to the literature on charge fractions at low energies, around and way below Bohr velocity, was done by various space research groups [25,26,27,28,29,30], developing new models applicable in this region [31].

Results

Conclusion