Ion Beam Analytical Methods

We use high energetic ions (H⁺, H₂⁺, He⁺ with an energy of ~2-3 MeV) to investigate and analyse samples. The ions penetrating the sample (also called target) interact with the electrons and nuclei in the sample. This leads to an excitation of electron shells, which rearrange under emission of electromagnetic radiation (X-rays and light). Furthermore the ions can be backscattered by the nuclei or even excite nuclei, which results in the emission of g-rays. Since the interaction processes depend on the encountered atoms, on the structure of the sample and on the sort and energy of the ions, the detection of secondary products of the interactions allows to determine the elemental content and distribution in a sample as well as crystal structure and quality by using the channeling effect.

For more information about the different IBA-methods click on the abbreviations in the following picture:

For the investigation of liquids we also apply the combination of Capillary Electrophoresis (CE) and PIXE, the PIXE-CE method.

Table 1: A brief overview about the characteristics of the IBA methods and XRF.

Analytical method	Typical application	Signal detected	Elements detected	Detection limits	Sampling depth
IL	Detection and speciation of REE in minerals Ion beam modification effects on luminescence properties of solids	light	depending on host material	> 0.1 ug/g	2 - 50 microns
PIGE	Determination of the elemental content	g-rays	B - P	100 ug/g	2 - 50 microns
PIXE	Determination of the elemental content	X-rays	Na - U	0.3 - 100 ug/g	2 - 30 microns
RBS	Detection of the main elemental components Determination of the depth profile of heavier elements in matrices of light elements	backscattered ions	B - U	0.001 - 10 at%	2 - 20 nm
SEI	Imaging of the surface topology of the sample	secondary electrons	--	--	--
STIM	Determination of the mean mass density of the sample	transmitted ions	--	--	thickness of the sample
XRF	Determination of the elemental content	fluorescent X-rays	Na - U	1 ug/g	5 microns
IBICC