Muon imaging was originally proposed and demonstrated by Alvarez. The method was re-discovered and improved upon by a research team at Los Alamos National Laboratory, muon tomography is completely passive, exploiting naturally occurring cosmic radiation. This makes the technology ideal for high throughput scanning of volume material where operators are present, such as at a marine cargo terminal. In these cases, truck drivers and customs personnel do not have to leave the vehicle or exit an exclusion zone during scanning, expediting cargo throughput.