Abstract: According to the present invention there is provided an apparatus for radiographic inspection of an underwater object comprising: an x-ray source for generating an x-ray beam for directing at an object under inspection; and a power supply, for supplying electrical power to the x-ray source; wherein the x-ray source comprises a circular-path particle accelerator, which circular-path particle accelerator comprises a circular-path particle chamber and an electromagnetic accelerator for accelerating electrons within the chamber, and the power supply comprises at least one solid state capacitor for providing an alternating discharge current to drive the electromagnetic accelerator in the x-ray source. There is also provided a method for the radiographic inspection of an underwater object.