ive seen somethin on the net like the device in the devinci code.. it has been tested and used, although they have manage to use antimatter-matter collision they could only capture about 1/2 of the energy that was produced in the containment of the device and the rest was moving too fast it went straight through the magnetic field which was holding them.. when i can be bothered later ill search for it.. i think the devices name is something like BaBa