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A modern dental X-ray tube. The heated cathode is on the left. Centre is the anode which is made from tungsten and embedded in the copper sleeve. William Coolidge explains medical imaging and X-rays. An X-ray tube is a vacuum tube that converts electrical input power into X-rays. [1]
A cathode-ray tube (CRT) is a vacuum tube containing one or more electron guns, which emit electron beams that are manipulated to display images on a phosphorescent screen. [2] The images may represent electrical waveforms on an oscilloscope , a frame of video on an analog television set (TV), digital raster graphics on a computer monitor , or ...
The resulting strong electric field near the cathode accelerates ions to a sufficient velocity to create free electrons from the cathode material. Another mechanism to generate free electrons from a cold metallic surface is field electron emission. It is used in some x-ray tubes, the field-electron microscope (FEM), and field-emission displays ...
Crookes X-ray tube from around 1910 Another Crookes x-ray tube. The device attached to the neck of the tube (right) is an "osmotic softener". When the voltage applied to a Crookes tube is high enough, around 5,000 volts or greater, [16] it can accelerate the electrons to a high enough velocity to create X-rays when they hit the anode or the glass wall of the tube.
A beam of cathode rays in a vacuum tube bent into a circle by a magnetic field generated by a Helmholtz coil.Cathode rays are normally invisible; in this demonstration Teltron tube, enough gas has been left in the tube for the gas atoms to luminesce when struck by the fast-moving electrons.
This idea was quickly applied to X-ray tubes, and hence heated-cathode X-ray tubes, called "Coolidge tubes", completely replaced the troublesome cold cathode tubes by about 1920. [citation needed] In about 1906, the physicist Charles Barkla discovered that X-rays could be scattered by gases, and that each element had a characteristic X-ray ...
The following table compares cathode-ray tube (CRT), liquid-crystal display (LCD), plasma and organic light-emitting diode (OLED) display device technologies. These are the most often used technologies for television and computer displays.
In X-ray tubes, the heel effect or, more precisely, the anode heel effect is a variation of the intensity of X-rays emitted by the anode depending on the direction of emission along the anode-cathode axis. X-rays emitted toward the anode are less intense than those emitted perpendicular to the cathode–anode axis or toward the cathode. The ...