We successfully evaluated the possibility of using a pulsed monoenergetic proton beam as a diagnostic tool for semiconductor detectors' response mapping at high charge densities. In order to ease the setup of the detector under test we explored the opportunity of performing tests with protons in air. We qualified a polyimide film window (Upilex-S, 7.5 μm nominal thickness) as proton extraction window and the energy loss in air as a function of distance. The tests have been carried out in vacuum first, in order to evaluate the energy loss due to the window only, followed by in-air tests aimed at the investigation of the total energy degradation of the extracted proton beam.