  One of the possible ways to maintain the micrometer spatial resolution while
performing ion beam analysis in the air is to increase the energy of ions. In
order to explore capabilities and limitations of this approach, we have tested
a range of proton beam energies (2 - 6 MeV) using in-air STIM (Scanning Ion
Transmission Microscopy) setup. Measurements of the spatial resolution
dependence on proton energy have been compared with SRIM simulation and
modelling of proton multiple scattering by different approaches. Results were
used to select experimental conditions in which 1 micrometer spatial resolution
could be obtained. High resolution in-air microbeam could be applied for IBIC
(Ion Beam Induced Charge) tests of large detectors used in nuclear and high
energy physics that otherwise can not be tested in relatively small microbeam
vacuum chambers.
