The section 2 of the emulsion spectrometer is dedicated to the charge measurement. We will show the results for the exposure $^{16}$O@200 MeV on C$_2$H$_4$, done at GSI in 2019.
For the evaluation of differential cross section, the association of tracks in S2 to vertices is crucial. A multivariate approach has been investigated to select vertices coming from the beam and reject those due to random tracks combinations. Results will be shown.