Ion beams accelerated to high energies can be used not only for material modification but also for detailed characterization of elemental composition and structure. Ion Beam Analysis (IBA) techniques provide a powerful, fully non-destructive approach for investigating materials. In these methods, the sample serves as a target for a beam of accelerated particles.
Interactions between the incident ions and the atoms (or nuclei) of the target lead to the emission of secondary radiation—such as characteristic X-rays, gamma rays, or scattered particles—whose energies are specific to the emitting species. This radiation is detected and energy-analyzed using appropriate detectors, enabling the simultaneous identification and quantification of multiple elements within a single measurement.
IBA experiments performed with the Tandetron accelerator include techniques such as Particle-Induced X-ray Emission (PIXE) and Rutherford Backscattering Spectrometry (RBS).
In PIXE analysis, interactions between incident ions and target atoms result in the emission of characteristic X-rays. The energies of these X-rays are measured using a Si(Li) detector. Since each element produces a unique set of spectral peaks, PIXE enables precise identification of elemental composition. This technique is particularly well suited for the analysis of a wide range of materials, including aerosol filters, environmental samples, and cultural heritage objects.
In RBS, the recorded energy spectrum is determined by the energy loss of incident ions (such as hydrogen or heavier particles) as they traverse the sample, as well as by the kinematics of their elastic collisions with target nuclei. The positions of peaks and edges in the spectrum provide information about the thickness and elemental composition of individual layers. The detected ion energies are directly related to the depth distribution of elements: thin layers produce sharp spectral features, while thicker layers result in broader peaks.
Using RBS, it is possible to determine:
– Elemental composition and stoichiometry (independent of chemical bonding),
– Depth distributions of elements,
– The location of impurities in single crystals when channelling mode is employed.
Detection equipment for materials structural and elemental analysis :
- ORTEC CR-015-050-100 is used for backscattering experiments. It has 15 keV alpha resolution (FWHM) at 5.486 MeV energy and 50 mm2 active area.
- Canberra 7905-BWR bellows-sealed windowless retractable cryostat is used for PIXE experiments. It has lithium-drifted silicon 30 mm2 active area, detector resolution (FWHM) is 165 eV at 5.894 keV for 55Fe X-ray peak.
