Fig. 7: NFC signal and triangulation from CEA data.

a–c Raw muographies obtained with Degennes-1, Joliot and Charpak-2. d–f Ratio between the data and the simulation for these three instruments, showing good overall agreement except in the summit direction where the statistics is very low. The horizontal, dashed red lines indicate the limit of the NFC obtained by slicing each image. g Triangulation of the NFC using the five instruments, where each cone represents the extremity of the NFC found in one data set (i.e., the directions defined by the red lines in plots (d–f)). The width of each cone represents the uncertainty of its direction, i.e., from 0.5 to 1.5°. The arrows show the orientation of each instrument. The yellow rectangle represents the position and size of the NFC as determined from the CEA analysis. h–j Same ratio as in d–f, obtained with a simulation containing a void representing the NFC, whose dimensions are described in the text. The excess seen in d–f has largely disappeared.