Upgrade of the external beamline at the microanalytical center of the Jožef Stefan Institute

Abstract The existing external beamline at the Microanalytical Centre of the Jožef Stefan Institute (JSI) in Ljubljana has been upgraded in order to extend the capabilities towards in-air PIXE imaging across relatively large sample surface area (∼1 cm2) with lateral resolution of sub 100 µm. For that purpose, a doublet of magnetic quadrupole lenses was installed on the beamline together with the newly designed exit nozzle with a 200 nm Si3N4 exit window resulting finally in ∼ 50 × 50 μm2 lateral resolution. Additionally, an in-vacuum beam chopper was installed before the exit nozzle to measure the proton dose deposited on the sample. The beam characterization results are presented together with the first application from the field of biology, namely quantitative concentration maps of a longitudinal section of a whole thick wheat grain.