First results on material identification and imaging with a large-volume muon tomography prototype.

The muon tomography technique, based on the multiple Coulomb scattering of cosmic ray muons, has been proposed recently as a tool to perform non-destructive assays of large volume objects. Experimental results are reported from a large volume (about 11 m3) scanning system prototype, assembled using two large area CMS Muon Barrel drift chambers. The imaging capabilities of the system and the first measurements of the capability of the technique to discriminate among different materials are presented.