A truck or vehicle mounted apparatus for Flash X-ray irradiation of material for sterilization includes a Flash X-ray source comprised of an electron gun and an anode. The electron gun comprises a field emission cold cathode having an electron emitting surface, and a grid for controlling electron flow from the cathode to the anode. The anode has an electron-receiving main surface and an X-ray emitting, oppositely facing main surface. The X-ray emitting surface, emits X-radiation into an irradiation volume. The X-ray emitting surface of the anode has orthogonally oriented first and second dimensions of greater than 2 millimetres each. A high voltage pulse power supply, connected to the vehicles electricity generator and with a supplemental energy storage capacitor, powers the Flash X-ray source. The cathode, grid and anode are located in a high vacuum housing. The electron gun, anode and high voltage pulse power supply are constructed as to create X-radiation in said irradiation volume to achieve a measured level of irradiation of the material in the irradiation volume as measured by a sensor. The material to be irradiated is moved through the high vacuum chamber by the vehicle mounted venturi pump. A turbojet powers both the electricity generator and vacuum pump.
