The quantitative two-dimensional areal density can be revealed from the scanning transmission ion microscopy (STIM) image of the sample owing to the relationship between the beam energy loss and the sample areal density. The obtained areal density map can provide fine spatial resolution to identify microstructures. Furthermore, this information can be used to achieve more precise quantification on X-ray absorption if simultaneously performing PIXE analysis. The development of STIM tomography enables to access the inner structure of the sample, especially in studying biological specimens. However, STIM tomography requires a large number of projections while stereo-STIM pair projections provide a quick tool for imaging the shape of the sample and determining the relative position, orientation and shape of the internal and external structures. Stereo-STIM experiments using 2 MeV proton microbeam were carried out on an insect and transmitted energies data were simultaneously collected by two surface barrier detectors mounted on 30° and -30° with respect to the beam direction. The defined disparity value resolved the features of different parts of the body of an insect not seen in individual STIM data.
