Related topics: black holes · radiation · wavelength · protein · laser

Happy hour for time-resolved crystallography

Researchers from the Department of Atomically Resolved Dynamics of the Max Planck institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg, the University of Hamburg ...

Elaborate Komodo dragon armor defends against other dragons

Just beneath their scales, Komodo dragons wear a suit of armor made of tiny bones. These bones cover the dragons from head to tail, creating a "chain mail" that protects the giant predators. However, the armor raises a question: ...

Global trade of tree seeds can introduce harmful pests

The trade of forest tree seeds is, on a global scale, not as safe as previously believed. Researchers from CABI and, among other institutions, the Swiss Federal Institute WSL, revealed that insect pests and fungal pathogens ...

Science puts historical claims to the test

The latest analytical techniques available to scientists can confirm the validity of historical sources in some cases, and suggest a need for reconsideration in others.

New structure for human flu virus protein

Researchers from Oxford University have worked out the molecular structure of a protein that is vital for survival of the flu virus. Recently published in Nature, they used several different techniques to look at the arrangement ...

NASA satellite spots a mystery that's gone in a flash

Pops of bright blue and green in this image of the Fireworks galaxy (NGC 6946) show the locations of extremely bright sources of X-ray light captured by NASA's NuSTAR space observatory. Generated by some of the most energetic ...

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X-ray

X-radiation (composed of X-rays) is a form of electromagnetic radiation. X-rays have a wavelength in the range of 10 to 0.01 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz (3 × 1016 Hz to 3 × 1019 Hz) and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays. In many languages, X-radiation is called Röntgen radiation after Wilhelm Conrad Röntgen, who is generally credited as their discoverer, and who had called them X-rays to signify an unknown type of radiation.:1-2

X-rays are primarily used for diagnostic radiography and crystallography. As a result, the term X-ray is metonymically used to refer to a radiographic image produced using this method, in addition to the method itself. X-rays are a form of ionizing radiation and as such can be dangerous.

X-rays from about 0.12 to 12 keV are classified as soft X-rays, and from about 12 to 120 keV as hard X-rays, due to their penetrating abilities.

The distinction between X-rays and gamma rays has changed in recent decades. Originally, the electromagnetic radiation emitted by X-ray tubes had a longer wavelength than the radiation emitted by radioactive nuclei (gamma rays). So older literature distinguished between X- and gamma radiation on the basis of wavelength, with radiation shorter than some arbitrary wavelength, such as 10−11 m, defined as gamma rays. However, as shorter wavelength continuous spectrum "X-ray" sources such as linear accelerators and longer wavelength "gamma ray" emitters were discovered, the wavelength bands largely overlapped. The two types of radiation are now usually defined by their origin: X-rays are emitted by electrons outside the nucleus, while gamma rays are emitted by the nucleus.

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