[en] Sections of interplanetary dust particles (IDPs) have been analyzed with proton-induced X-ray emission (PIXE) and scanning transmission ion microscopy (STIM) in order to determine trace element contents and distributions on a micrometer scale as well as particle densities and masses. To accomplish this, several improvements of the proton microprobe and of the data acquisition system, as well as special sample preparation were necessary

[en] During PIXE analyses of biomedical samples often great damage of the sample occurs. This damage is always combined with mass loss and strong alterations of the initial structure. The loss of mass can be explained by the loss of volatile elements, mainly the major elements Hydrogen, Carbon, Nitrogen, and Oxygen. This results in a charge dependency of the element contents and has to be corrected during the data reduction. Here we describe measurements of different samples that monitor the mass loss and the charge dependency of the trace element concentrations. A model was developed to give the correct concentrations after the PIXE analyses. Additionally first results of PIXE analyses of gum tissue are reported. They give direct hints for amalgam residues inside the tissue in pathologically altered areas. (author)

[en] We developed a new technique to determine the impact position of single pencil beams in the image plane with an accuracy of 0.2 μm. This technique bases on the overlapping of secondary electron images from a 1000 mesh grid. The measurements themselves can be obtained without any change in the routine setup if a secondary electron counter is installed. By choosing different object positions (x₀, y₀) and divergence angles (θ₀, phi for the pencil beam the characteristics of the used lens system can be analysed and the lens errors can be calculated with high precision. Results for the Heidelberg quadrupole doublet will be reported

[en] The properties of a clinical LINAC are investigated for a study of photoactivation cross-sections slightly above the neutron threshold. As an example, the photoactivation of a tiny amount of gold by the ¹⁹⁷Au(γ,n)¹⁹⁶Au reaction has been measured. The derived photon intensity is at least comparable to conventional and widely used photon sources. In combination with its extremely stable operation, a clinical LINAC ensures that photoactivation studies can be performed for a wide number of targets with very limited beamtime