Ion beam analysis

Ion beam analysis (IBA) is an important family of modern analytical techniques involving the use of MeV ion beams to probe the composition and obtain elemental depth profiles in the near-surface layer of solids. IBA is not restricted to MeV energy ranges. It can be operated at low energy (<Kev) using techniques such as FIB, and Secondary ion mass spectroscopy, as well as at higher energies (>GeV) using instruments like the LHC. All IBA methods are highly sensitive and allow the detection of elements in the sub-monolayer range. The depth resolution is typically in the range of a few nanometers to a few ten nanometers. Atomic depth resolution can be achieved, but requires special equipment. The analyzed depth ranges from a few ten nanometers to a few ten micrometers. IBA methods are always quantitative with an accuracy of a few percent. Channeling allows to determine the depth profile of damage in single crystals.

• RBS: Rutherford backscattering is sensitive to heavy elements in a light matrix. This technique is used for determining elemental composition and depth profiling of materials.
• EBS: Elastic (non-Rutherford) backscattering spectrometry can be sensitive even to light elements in a heavy matrix. The term EBS is used when the incident particle is going so fast that it exceeds the "Coulomb barrier" of the target nucleus, which therefore cannot be treated by Rutherford's approximation of a point charge. In this case Schrödinger's equation should be solved to obtain the scattering cross-section (see http://www-nds.iaea.org/sigmacalc/ Archived 2013-07-28 at the Wayback Machine).
• ERD: Elastic recoil detection is sensitive to light elements in a heavy matrix
• PIXE: Particle-induced X-ray emission gives the trace and minor elemental composition
• NRA: Nuclear reaction analysis is sensitive to particular isotopes
• Channelling: The fast ion beam can be aligned accurately with major axes of single crystals; then the strings of atoms "shadow" each other and the backscattering yield falls dramatically. Any atoms off their lattice sites will give visible extra scattering. Thus damage to the crystal is visible, and point defects (interstitials) can even be distinguished from dislocations.
• IBIL: Ion beam induced luminescence occurs when an energetic beam of ions strike a target, excite the native atoms, and visible light is emitted as a result of outer-shell transitions.^[1]

The quantitative evaluation of IBA methods requires the use of specialized simulation and data analysis software. SIMNRA and DataFurnace are popular programs for the analysis of RBS, ERD and NRA, while GUPIX is popular for PIXE. A review of IBA software^[2] was followed by an intercomparison of several codes dedicated to RBS, ERD and NRA, organized by the International Atomic Energy Agency.^[3]

IBA is an area of active research. The last major Nuclear Microbeam conference in Debrecen (Hungary) was published in NIMB 267(12–13).