The goal of the project is to find new knowledge based on experimental study of the radiation damages induced by energetic (MeV) ion beams. The focus is on studying:

Wide variety of ion beams in terms of both ion species and ion energy which can be delivered from 6 MV Tandem Van de Graaff accelerator at RBI will be used for materials modifications. 2 MeV protons, He (when available) and Lithium from 1 MV Tandetron accelerator will be used for monitoring ion track formation kinetics using RBS/c. In-situ analysis of ion track formation using RBS/c on the existing dual-beam chamber and ex-situ experiments elsewhere will be performed on selected materials like SrTiO₃, TiO₂ and GaN. Potential material of interest could be CaF₂. SiO₂ quartz could be used for testing purposes, in order to demonstrate effectiveness of our proposed set-up and to quantify damage due to probing RBS/c beam. Another Ion Beam Analysis (IBA) methods available at the local tandem Accelerator Facility will be used as needed, such as  PIXE, TOF-ERDA, NRA. All the above could be extended with use of facilities from our collaborators. In particular, selected samples can be irradiated using swift heavy ion beams at GANIL and highly charged ion beams at University of Duisburg-Essen. Complementary measurements, in particular ex-situ AFM are planned using existing AFM set-up at RBI. Also, in case of difficulties, or in case of interesting findings, high resolution AFM on selected samples can also be done at University of Duisburg-Essen. Additionally, structural data on ion tracks on surfaces and in the bulk can be obtained using GISAXS and TEM techniques, respectively. Swelling of the samples can also be investigated using profilometry. Optical properties of the ion irradiated materials can be probed using spectroscopic ellipsometry technique.Obtained experimental data will be treated using existing thermal spike models.

We will study channeling implantation by MeV ions in selected materials using ion axial channeling effect. Channelling implantation profiles will be studied by means of ion channelling spectra in the backscattering geometry, and PIGE, NRA, PIXE and SEM as needed. This will be an effort in continuation to our first channelling experiments performed recently on silicon.These experiments will also help us to establish the capability to conduct dual-ion irradiations that capture the key elements of the fusion neutron spectrum, estimate micro-structural changes in selected irradiated material of interest for fusion energy by channelling/random RBS/PIXE/PIGE, IBIC and SEM/TEM analyses and describe (experimental and/or computational) development and evolution of micro-structural changes in irradiated material in dependence on ion species, energies and doses. Complementary measurements will be performed with our collaborators.

Within this objective it has been planned to use dual beam scattering chamber in such a way that one ion beam will be used as a damaging beam, while the other one with the ion beam current reduced to approximately 1000 ions/sec will be used to probe the changes in electronic transport by IBIC measurement to extend knowledge about the radiation defect kinematics that could be important to other uses of materials like for example diamond and SiC. The nature of electric field polarisation is another effect that will be possible to explore with this approach. In order to be able to extract basic parameters of charge carrier transport in relationship to all parameters that will be varied (including materials) modelling of charge transport response will have to be used. In case of experimental difficulties associated with the use of collimated beams, focused ion beams will be used to perform IBIC measurements using the RBI ion microprobe.

Hrvatska zaklada za znanost (HRZZ) – Croatian Science Foundation

15.06.2014. – 14.06.2018.