Muon tomography of large structures with 2D projections

A large scale 3D reconstruction using a combination of 2D transmission muography projections is presented. This reconstruction is based on the implementation of the SART algorithm used in medical imaging and recently applied to small objects in the absorption mode. Several challenges had to be faced, in particular the lack of open-sky (total flux) measurements during the transmission data taking, the enormous size of the matrix system to be solved and the combination of projections obtained at different positions. The algorithm was successfully tested on a simulated geometry of a simple but large object with realistic density differences. In spite of the low number of 2D projections, it provided precise results on the 3D shape without any prior assumptions on the internal structure of the scrutinized object.