Heidelberg proton microprobe

Particle-induced x-ray emission (PIXE), which has been used extensively in the trace element analysis of large samples, is successfully applied to the analysis of microvolumes. This development was stimulated by experiences with the collimation and focussing of heavy-ion beams which led to a feasible design for a proton microprobe. In the Heidelberg microprobe the beam is focussed to a spot size of 2 μm x 2 μm by means of a specially designed quadrupole doublet. The recently approved secondary electron imaging system allows fast focussing and positioning of the beam on the sample. Such a system so far provides the only possibility to reach lateral resolutions less than 1 μm. The microprobe has been used for the analysis of mineralogical and biological samples