Tungsten X-ray Tubes for Radiation Source

Tungsten x-ray tubes provide a means for generating x-ray radiation in most analytical instruments.

An evacuated tube houses a tungsten alloymaterial which acts as a cathode opposite to a much larger, water cooled anode made of copper with a metal plate on it. The metal plate can be made of any of the following metals: tungsten, copper, cobalt and iron, etc.. A high voltage is passed through the tungsten alloy material and high energy electrons are produced. The machine needs some way of controlling the intensity and wavelength of the resulting light. The intensity of the light can be controlled by adjusting the amount of current passing through the filament; essentially acting as a temperature control. The wavelength of the light is controlled by setting the proper accelerating voltage of the electrons. The voltage placed across the system will determine the energy of the electrons traveling towards the anode.

X-rays radiation source is produced when the electrons hit the target metal. Because the energy of light is inversely proportional to wavelength (E=hc=h(1/λ), controlling the energy, controls the wavelength of the x-ray beam.

Why Tungsten Target for X-Ray Tube is Good?

Tungsten target implies an X-ray tube where high energy electrons are directed in a vacuum to strike a tungsten target. Where the electrons strike the tungsten very short wavelength X-rays are generated and pass out through the vacuum tube for use in medical diagnosis and engineering radiography of welds and castings etc. Tungsten target is usually used in x-ray tube, there are usually two reasons for these application:

1. Tungsten has a relatively high density, which could protect relatively high energy characteristic x-rays.

2. Tungsten has the highest melting point of any metal, and because over 99% of the energy put into the x-ray tube to produce the beam is turned into heat energy, the ability to disparate the heat without loosing structural integrity is critical.

For more details, you could visit tungsten target X-ray.