Scatter plot of all simultaneous measurements (RPC-MIP and RPC-LAP measurements where made within 1 sec, considering only RPC-MIP phased SDL sub-mode) showing RPC-MIP total electron density, expressed in cm⁻³ versus the RPC-LAP I-V curve slope, expressed in nA/V. Measurements are subdivided in three cases: RPC-LAP and RPC-MIP both observed cold electrons (blue points), RPC-LAP observed cold electrons while RPC-MIP did not (green points) and RPC-MIP observed cold electrons while RPC-LAP did not (red points). The grey horizontal bars indicate the electron density corresponding to the well-known RPC-MIP interferences (see Sect. 2.2).