Potential energy retention of highly charged ions in solid surfaces


Potential energy retention of highly charged ions in solid surfaces

Facsko, S.; Kost, D.; Möller, W.; Zschornack, G.; Hellhammer, R.; Stolterfoht, N.

In the interaction of highly charged ions with solid surfaces a main interest lies in the study of the dissipation channels for the potential energy. A large amount of information about secondary electron emission and X-ray emission has been collected in the past, enlightening the physics of the relaxation process of HCIs at surfaces. Calculating the amount of energy, which is dissipated into these channels only 10% to 15% is obtained. Less information is available about the absolute amount of the potential energy, which is deposited into the surface. In view of possible applications of HCIs for surface modifications the knowledge of this amount is essential.
In order to study the energy retention of the potential energy of HCIs into solid surfaces, we apply a calorimetric approach [1]. The ions (charge state q=2 .. 8) are extracted from an ECR ion source with 5 kV and decelerated to final kinetic energies down to 60 eV x q after beam transport and charge state separation. By using a liquid-nitrogen cooled calorimetric setup the retention of the total energy, kinetic and potential, is determined via the temperature increase during the bombardment. Measuring the energy retention at kinetic energies from 200 – 60 eV and extrapolating to 0 eV kinetic energy the separated potential energy is obtained. The experiments were done on clean Cu, Si, and SiO2 surfaces.
Here, we present a comparative study of the relative retention coefficients of the potential energy for the metallic, semiconductor, and insulator surfaces. In addition, measurements of the secondary electron yield are taken into consideration for a detailed picture of the energy dissipation channels.
[1] U. Kentsch, G. Zschornack, H. Tyrroff, and W. Möller, Phys. Rev. Lett. 87, 105504 (2001)

Keywords: highly charged ions

  • Lecture (Conference)
    12th International Conference on the Physics of Highly Charged Ions, 06.-11.09.2004, Vilnius, Lithuania

Permalink: https://www.hzdr.de/publications/Publ-7091
Publ.-Id: 7091