Total Ion Beam Analysis - IBC Leads the Way

Friday 17 February 2012

"Total IBA" is a very powerful new ion beam analysis characterisation technique enabling the unambiguous depth profiling of very complex thin films,  and in principle making chemical tomography of small samples feasible.  This new method, which we have been instrumental in developing, fully exploits the complementary information available from the photon and particle methods: with the depth resolution and traceability of RBS and the mass resolution and sensitivity of PIXE. And all this at the lateral resolution given by our microbeam.

"Total IBA" is the idea of using multiple IBA techniques self-consistently,  in particular X-ray emission (PIXE) and particle backscattering (BS).  We have known for decades that PIXE and BS are complementary:  PIXE has high sensitivity and excellent elemental discrimination where RBS has good depth resolution and excellent accuracy.  But only in the last five years has their synergistic treatment become possible in a routine way using the DataFurnace software.  This is because a) the PIXE module is new (He-PIXE was implemented only last year),  and b) the backscattering signal for typical PIXE analyses is almost always non-Rutherford.  Elastic (non-Rutherford) backscattering (EBS) cross-sections must be calculated from Schrödinger’s equation and nuclear data for accurate work,  and these cross-sections have only recently become available (see “Development of a reference database for Ion Beam Analysis and future perspectives”)

Those interested can read further in two major Reviews just published:
"Total IBA,  where are we?" (Nucl. Instr. Methods Phys. Res. B, 271, 2012, 107-118)
"Ion Beam Analysis : a century of exploiting the electronic and nuclear structure of the atom for materials characterisation".  (Reviews of Accelerator Science and Technology, 4, 2011, 41-82: 31 Figures, 290 references)