A radiographic inspection system for inspecting subject objects using charged particle beams having pulses of charged particles with different energy levels from pulse to pulse. A phase shifter thereof enables adjustment of the RF power delivered to first and second accelerating sections thereof from a single RF source without adjustment of the RF power generated by the RF source. The system also enables the generation of images of the contents of a container from multiple directions and in multiple planes, and allows the discrimination of materials present in the container.