Scanning Microprobe SNAKE :: LRT2 - Institute of Applied Physics and Metrology

The Scanning microprobe SNAKE (Supraleitendes Nanoskop für angewandte kernphysikalische Experimente = superconducting nanoprobe for applied nuclear physics experiments) at the 14MV Munich Tandem Accelerator can focus an ion beam to a submicrometer beam size. By newly desingned object slits the ion beam is trimmed to a diameter of about 20 µm. This object is demagnified by a triplet of superconducting quadrupole lenses with multipole correction by a factor of up to 200 (depending on the application).

This makes standard analysis for nuclear microprobes with lateral resolution in submicrometer range available. Beyond this one can do a hydrogen microscopy with best sensitivity and lowest radiation damage by coincident measurement of elastic proton-proton-scattering.

At the moment SNAKE is mainly used for well directed irradiation of living cells with single ions. The ions induce various damages to the DNA in the cells of which double strand breaks (DSBs) are the most grave. To the DSBs accumulate various repair proteins in clusters (so called foci), which can be made visible under the microscope in fixed cells by immunofluorescence techniques. The microscopic pictures allow qualitative and quantitative analysis of the dynamics of the repair proteins but also of the damaged DNA itself.

Such a microscopic picture represents a snapshot of the cell in the moment of fixation. Thus there will be built a live cell microscopy equipment at the irradiation site, which allows to watch dynamics within one cell.

Further information can be found at the SNAKE homepage of the institute E12 at TU München.