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

Making metal with the lightness of air

Gold, silver and copper are heavy metals, but LLNL scientists can now make them nearly as light as air—in a form so tiny it can ride on a mosquito's back.

The most complete study of battery failure sees the light

An international team of researchers just published in Advanced Energy Materials the widest study on what happens during battery failure, focusing on the different parts of a battery at the same time. The role of the ESRF, ...

Heart of lonesome galaxy is brimming with dark matter

Isolated for billions of years, a galaxy with more dark matter packed into its core than expected has been identified by astronomers using data from NASA's Chandra X-ray Observatory.

Mars on Earth: What's next?

A Mars sample return campaign would bring samples of the Red Planet back to Earth for examination in the best terrestrial laboratories—but choosing the samples and storing them on Mars for later return is only one part ...

Chandra finds stellar duos banished from galaxies

Scientists have found evidence that pairs of stars have been kicked out of their host galaxies. This discovery, made using data from NASA's Chandra X-ray Observatory, is one of the clearest examples of stellar pairs being ...

Astronomers investigate pulsar wind nebula DA 495

Astronomers have carried out a multiwavelength investigation of a pulsar wind nebula (PWN), designated DA 495, to unveil its mysterious physical nature. Results of the study, based on observations using HAWC and VERITAS ground-based ...

Does the gas in galaxy clusters flow like honey?

We have seen intricate patterns that milk makes in coffee and much smoother ones that honey makes when stirred with a spoon. Which of these cases best describes the behavior of the hot gas in galaxy clusters? By answering ...

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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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