X ray

A high-energy photon, usually produced by cathode rays or emitted by electrons falling to lower energy states in atoms. The range of frequencies in the electronic spectrum lying between the ultraviolet (3x10¹⁶Hz) and the gamma rays (10²¹Hz), wavelengths from a few picometers up to 20 nanometers.

Some properties of X-rays:

• Travel in straight lines at the speed of light.
• Not deflected by electric or magnetic fields.
• Penetrate matter.
• They can be reflected.
• Refractive index is close to 1 for all materials.
• They can be diffracted.
• They ionize gases through which they pass.
• They affect photographic film.
• They can produce fluorescence.
• They can produce photoelectric emission

Discovered by Willhelm Conrad Röntgen (1845-1923) in November 1895.

Usually produced by fast electrons going through matter or by the de-excitation of excited atoms.

They are used to take medical photographs of internal organs and bones.

X-rays in high doses can damage living cells.

Hard X-rays

Higher-energy part of the X-ray spectrum ranging from approximately 5 keV to 100 keV.

Soft X-rays

Band of low energy X-rays, between 0.1 keV and approximately 5 keV.

See also: Characteristic X-ray, Gamma Rays, Ultraviolet Light.