Also known as x-radiography and gamma radiography. X-rays are produced by high voltage x-ray machines, whereas gamma rays are produced from radioactive isotopes such as Iridium 192 and Cobalt 60. The x-ray or gamma rays are placed close to the material to be inspected and they pass through the material and are then captured on film. This film is then processed and the image is obtained as a series of grey shades between black and white. Gamma sources have the advantage of portability which makes them ideal for use in site working.
X-rays and gamma rays are very hazardous. Special precautions must be taken when performing radiography. Therefore the operator will use these inside a protective enclosure or with appropriate barriers and warning signals to ensure there are no hazards to personnel.
