The image intensifier consists of a scintillator input window, a photocathode, electro-optics, a luminescent screen and an output window- all contained in an evacuated enclosure. The X-rays then strike the scintillating layer of the input screen of the image intensifier, where they are transformed into optically visible rays of light. The emitted photons hit a photocathode converting them to electrons. These electrons are accelerated and focussed by means of electrical fields. The electrons are then hurled against a phosphorus screen that changes the amplified electrons back into visible light, creating a smaller, very bright image against the output window. Behind the output screen, a digital CCD camera captures the image on the output window for further image processing purposes and display on a monitor.