Fig. 1
From: Helium ion beam imaging for image guided ion radiotherapy
Experimental setup consisting of the front tracker, PMMA phantom with 1 mm air inhomogeneity, energy deposition detector and the rear tracker. FitPIX interfaces are used for data readout and synchronization. Data are saved to a laptop. Dimensions are not to scale. The PMMA phantom is 161 mm long, with the air inhomogeneity exactly in the middle. The pencil beam has energy of 168.3 MeV/u and width of 4.5 mm (FWHM)