P. Arndt et al., ON THE ACCURACY OF ELEMENT CONCENTRATIONS AND MASSES OF MICRON-SIZED SAMPLES DETERMINED WITH THE HEIDELBERG PROTON MICROPROBE, Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms, 130(1-4), 1997, pp. 192-198
We have already tested the reliability of element-normalized PIXE (Pro
ton Induced X-ray Emission) data on small (10-100 mu m) particles that
we routinely obtain with the Heidelberg proton microprobe. Thus, we h
ere discuss the accuracy of quantitative results, i.e., absolute conce
ntrations inferred from PIXE analyses of such particles. We investigat
ed and reduced the effects of mechanical vibrations and of the instabi
lity of the electronic devices on the achievable minimum beam spot. We
implemented into our computer code a mapping software for qualitative
element distributions (PIXE) and quantitative mass images using STIM
(Scanning Transmission Ion Microscopy). The STIM images determine the
area density required to calculate from PIXE spectra the absolute elem
ent concentrations in thin samples. The accuracy of absolute PIXE conc
entrations is tested by measurements on 15 mu m soda lime glass micros
pheres. Finally, the complete results of PIXE and STIM analyses of an
interplanetary dust particle (IDP) are described.