[NanoIC topic] Energy loss of propagating heavy ions in SiN and Au nanometric thin films

The study of the energy loss of ions propagating in matter is crucial for advancing various fields such as ion implantation, ion beam analysis, nuclear physics, outer space exploration and radiation therapy. The rate of energy loss of an ion per unit path length normalized to the atomic density is called the stopping cross section and may be expressed in units of 10^-15 eV cm². The stopping cross section depends on the velocity or kinetic energy of the moving projectile and on the type of target atoms. At projectile energies between 100 keV/u and 100 MeV/u, the energy loss is dominated by interactions of the moving ion with the electrons in the target, referred to as electronic energy loss.

The energy loss of light ions (H or He) in various elemental matrices has been experimentally studied in detail [1]. This has allowed one to refine theoretical models and simulation tools to reach an accuracy of better than 5%. However, there are only limited experimental results for propagating ions heavier than He. As a result, generalizing models with an appreciable uncertainty are used for analytical techniques such as heavy-ion elastic recoil detection analysis (ERD).

To gain more insight into ion–matter interactions and to advance the accuracy of heavy-ion ERD, we will investigate the characteristic energy loss of projectiles heavier than H and He in target materials such as SiN and Au. You will take part in the design, the construction, and the optimization of a new experimental setup. You will conduct the energy loss experiments at the 2MV tandem electrostatic particle accelerator.

An essential aspect of the work is the data analysis and interpretation. Experimentally obtained energy loss values will be extracted from the measurements and compared with existing models and databases (e.g. SRIM [2]) to assess their accuracy. The expected outcome of the project is a validated experimental methodology for stopping power measurements and its implementation in our laboratory. You will contribute new experimental data for selected projectile-target combinations which will be used to refine existing parametrizations.

[1] H. Paul, Stopping Power Database, available at https:/www-nds.iaea.org/stopping/ (accessed August 15, 2023); IAEA Stopping Power Database, version 2023-11, https://nds.iaea.org/stopping (accessed Dec. 12, 2025).

[2] J.F. Ziegler, J.P. Biersack, M.D. Ziegler, SRIM 2008. http://www.srim.org (accessed Jan. 1, 2025