query: Who discovered x-rays?

title: X-ray tube

text: voltages in the event of failure. The hazard associated with excessive voltages was eliminated with the advent of all solid state TVs, which have no tubes beside the CRT. Since 1969 the FDA has limited TV X-ray emission to 0.5 mR (milliroentgen) per hour. The flat screens used today do not have any vacuum tubes capable of emitting X-rays. X-ray tube An X-ray tube is a vacuum tube that converts electrical input power into X-rays. X-ray tubes evolved from experimental Crookes tubes with which X-rays were first discovered on November 8, 1895, by the German physicist Wilhelm Conrad Röntgen. The

title: Orthovoltage X-rays

text: to reach shallow tumors, but to treat tumors deep in the body more voltage was needed. By the 1930s and 1940s megavoltage X-rays produced by huge machines with 3-5 million volts on the tube, began to be employed. With the introduction of linear accelerators in the 1970s, which could produce 4-30 MV beams, orthovoltage x-rays are now considered quite shallow. Orthovoltage X-rays Orthovoltage x-rays are produced by x-ray tubes operating at voltages in the 100–500 kV range, and therefore the x-rays have a peak energy in the 100–500 keV range. Orthovoltage X-rays are sometimes termed "deep" x-rays (DXR). They cover

title: Megavoltage X-rays

text: sites within the body. Lower energy x-rays, called orthovoltage X-rays, are used to treat cancers closer to the surface. Megavoltage x-rays are preferred for treatment of deep lying tumours as they are attenuated less than lower energy photons, and will penetrate further, with a lower skin dose. Megavoltage x-rays also have higher relative biological effectiveness than orthovoltage x-rays. These properties help to make megavoltage x-rays the most common beam energies typically used for radiotherapy in modern techniques such as IMRT. Use of megavoltage x-rays for treatment first became widespread with the use of Cobalt-60 machines in the 1950s. However prior

title: Orthovoltage X-rays

text: Orthovoltage X-rays Orthovoltage x-rays are produced by x-ray tubes operating at voltages in the 100–500 kV range, and therefore the x-rays have a peak energy in the 100–500 keV range. Orthovoltage X-rays are sometimes termed "deep" x-rays (DXR). They cover the upper limit of energies used for diagnostic radiography, and are used in external beam radiotherapy to treat cancer and tumors. They penetrate tissue to a useful depth of about 4–6 cm. This makes them useful for treating skin, superficial tissues, and ribs, but not for deeper structures such as lungs or pelvic organs. The energy and penetrating ability of

title: Superficial X-rays

text: locations, orthovoltage treatment is being replaced by electron therapy or brachytherapy. As well as teletherapy, X-rays in this energy range (and the low orthovoltage range) are used for imaging patients, to analyse materials and objects in industrial radiography and for crystallography. Superficial X-rays Superficial X-rays are low-energy X-rays that do not penetrate very far before they are absorbed. They are produced by X-ray tubes operating at voltages in the 10–100 kV range, and therefore have peak energies in the 10–100 keV range. Precise naming and definitions of energy ranges may vary, and X-rays at the lower end of this range

title: Superficial X-rays

text: Superficial X-rays Superficial X-rays are low-energy X-rays that do not penetrate very far before they are absorbed. They are produced by X-ray tubes operating at voltages in the 10–100 kV range, and therefore have peak energies in the 10–100 keV range. Precise naming and definitions of energy ranges may vary, and X-rays at the lower end of this range may also be known as Grenz rays. They are useful in radiation therapy for the treatment of various benign or malignant skin problems, including skin cancer and severe eczema. They have a useful depth of up to 5 mm. In some

title: The X-Rays

text: and Tom Green (a Brighton comedian). The X-Rays The X-Rays (also known as The X-Ray Fiend) is an 1897 British short silent comedy film, directed by George Albert Smith, featuring a courting couple exposed to X-rays. The trick film, according to Michael Brooke of BFI Screenonline, "contains one of the first British examples of special effects created by means of jump cuts" Smith employs the jump-cut twice; first to transform his courting couple via "X rays," dramatized by means of the actors donning black bodysuits decorated with skeletons, and then to return them to normal. The couple in question were

title: The X-Rays

text: The X-Rays The X-Rays (also known as The X-Ray Fiend) is an 1897 British short silent comedy film, directed by George Albert Smith, featuring a courting couple exposed to X-rays. The trick film, according to Michael Brooke of BFI Screenonline, "contains one of the first British examples of special effects created by means of jump cuts" Smith employs the jump-cut twice; first to transform his courting couple via "X rays," dramatized by means of the actors donning black bodysuits decorated with skeletons, and then to return them to normal. The couple in question were played by Smith's wife Laura Bayley

title: High-energy X-rays

text: (HEX-rays) between 100 and 300 keV bear unique advantage over conventional hard X-rays, which lie in the range of 5–20 keV They can be listed as follows: With these advantages, HEX-rays can be applied for a wide range of investigations. An overview, which is far from complete: High-energy X-rays High-energy X-rays or HEX-rays are very hard X-rays, with typical energies of 80–1000 keV (1 MeV), about one order of magnitude higher than conventional X-rays (and well into gamma-ray energies over 120 keV). They are produced at modern synchrotron radiation sources such as the beamline ID15 at the European Synchrotron Radiation

title: High-energy X-rays

text: High-energy X-rays High-energy X-rays or HEX-rays are very hard X-rays, with typical energies of 80–1000 keV (1 MeV), about one order of magnitude higher than conventional X-rays (and well into gamma-ray energies over 120 keV). They are produced at modern synchrotron radiation sources such as the beamline ID15 at the European Synchrotron Radiation Facility (ESRF). The main benefit is the deep penetration into matter which makes them a probe for thick samples in physics and materials science and permits an in-air sample environment and operation. Scattering angles are small and diffraction directed forward allows for simple detector setups. High-energy X-rays

title: Italian X Rays

text: Steve Miller wrote, in the liner notes to the Steve Miller Band "Box Set" (1994), "This is the last song I wrote with Tim Davis. Tim was dying at the time from diabetes and it had taken a terrible toll on him. But he never lost his good humor." Italian X Rays Italian X Rays is the thirteenth studio album by American rock band Steve Miller Band. The album was released in November 1984, by Capitol Records. "Who Do You Love?" and "Out of the Night" were songs co-written by Steve Miller and Tim Davis. Tim Davis had been a

title: Italian X Rays

text: Italian X Rays Italian X Rays is the thirteenth studio album by American rock band Steve Miller Band. The album was released in November 1984, by Capitol Records. "Who Do You Love?" and "Out of the Night" were songs co-written by Steve Miller and Tim Davis. Tim Davis had been a co-founder of the Steve Miller Band and had been a drummer, singer and songwriter with the band during its first five albums, released between 1968 and 1970. As of 1984, Davis was suffering from the effects of diabetes, and died four years later. Referring to "Out of the Night",

title: Orthovoltage X-rays

text: the x-rays produced by an x-ray tube increases with the voltage on the tube. External beam radiotherapy began around the turn of the 20th century with ordinary diagnostic x-ray tubes, which used voltages below 150 kV. Physicians found that these were adequate for treating superficial tumors, but not tumors inside the body. Since these low energy x-rays were mostly absorbed in the first few centimeters of tissue, to deliver a large enough radiation dose to buried tumors would cause severe skin burns. Therefore beginning in the 1920s "orthovoltage" 200–500 kV x-ray machines were built. These were found to be able

title: X-ray

text: X-ray X-rays make up X-radiation, a form of electromagnetic radiation. Most X-rays have a wavelength ranging from 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz (3×10 Hz to 3×10 Hz) and energies in the range 100 eV to 100 keV. X-ray wavelengths are shorter than those of UV rays and typically longer than those of gamma rays. In many languages, X-radiation is referred to with terms meaning Röntgen radiation, after the German scientist Wilhelm Röntgen who discovered these on November 8, 1895, who usually is credited as its discoverer, and who named it

title: X-ray

text: the absorbed dose. X-ray X-rays make up X-radiation, a form of electromagnetic radiation. Most X-rays have a wavelength ranging from 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz (3×10 Hz to 3×10 Hz) and energies in the range 100 eV to 100 keV. X-ray wavelengths are shorter than those of UV rays and typically longer than those of gamma rays. In many languages, X-radiation is referred to with terms meaning Röntgen radiation, after the German scientist Wilhelm Röntgen who discovered these on November 8, 1895, who usually is credited as its discoverer, and

title: Characteristic X-ray

text: is called the Auger effect. Characteristic X-rays can be used to identify the particular element from which they are emitted. This property is used in various techniques, including X-ray fluorescence spectroscopy, particle-induced X-ray emission, energy-dispersive X-ray spectroscopy, and wavelength-dispersive X-ray spectroscopy. Characteristic X-ray Characteristic X-rays are emitted when outer-shell electrons fill a vacancy in the inner shell of an atom, releasing X-rays in a pattern that is "characteristic" to each element. Characteristic X-rays were discovered by Charles Glover Barkla in 1909, who later won the Nobel Prize in Physics for his discovery in 1917. Characteristic X-rays are produced when an

title: Megavoltage X-rays

text: to this other devices had been capable of producing megavoltage radiation, including the 1930s Van de Graaff generator and betatron. Megavoltage X-rays Megavoltage X-rays are produced by linear accelerators ("linacs") operating at voltages in excess of 1000 kV (1 MV) range, and therefore have an energy in the MeV range. The voltage in this case refers to the voltage used to accelerate electrons in the linear accelerator and indicates the maximum possible energy of the photons which are subsequently produced. They are used in medicine in external beam radiotherapy to treat neoplasms, cancer and tumors. Beams with the voltage range

title: Megavoltage X-rays

text: Megavoltage X-rays Megavoltage X-rays are produced by linear accelerators ("linacs") operating at voltages in excess of 1000 kV (1 MV) range, and therefore have an energy in the MeV range. The voltage in this case refers to the voltage used to accelerate electrons in the linear accelerator and indicates the maximum possible energy of the photons which are subsequently produced. They are used in medicine in external beam radiotherapy to treat neoplasms, cancer and tumors. Beams with the voltage range of 4-25 MV are used to treat deeply buried cancers because radiation oncologists find that they penetrate well to deep

title: Spectrometer Telescope for Imaging X-rays

text: developed by an international collaboration led by the University of Applied Sciences and Arts Northwestern Switzerland. Spectrometer Telescope for Imaging X-rays The Spectrometer Telescope for Imaging X-rays (STIX) is one of the 10 instruments that are part of the scientific payload for the ESA Solar Orbiter mission, to be launched in 2020. The STIX instrument is an X-ray imaging spectrometer, whose purpose is to study the extremely hot solar plasma and the high-energy electrons accelerated during a solar flare. It can detect X-rays from 4 to 150 keV and exploits an indirect imaging technique based on the moiré effect, to

text: Spectrometer Telescope for Imaging X-rays The Spectrometer Telescope for Imaging X-rays (STIX) is one of the 10 instruments that are part of the scientific payload for the ESA Solar Orbiter mission, to be launched in 2020. The STIX instrument is an X-ray imaging spectrometer, whose purpose is to study the extremely hot solar plasma and the high-energy electrons accelerated during a solar flare. It can detect X-rays from 4 to 150 keV and exploits an indirect imaging technique based on the moiré effect, to produce images with few arcsec angular resolution in any given energy range. The instrument has been

title: Characteristic X-ray

text: Characteristic X-ray Characteristic X-rays are emitted when outer-shell electrons fill a vacancy in the inner shell of an atom, releasing X-rays in a pattern that is "characteristic" to each element. Characteristic X-rays were discovered by Charles Glover Barkla in 1909, who later won the Nobel Prize in Physics for his discovery in 1917. Characteristic X-rays are produced when an element is bombarded with high-energy particles, which can be photons, electrons or ions (such as protons). When the incident particle strikes a bound electron (the target electron) in an atom, the target electron is ejected from the inner shell of the

title: X-ray tube

text: X-ray tube An X-ray tube is a vacuum tube that converts electrical input power into X-rays. X-ray tubes evolved from experimental Crookes tubes with which X-rays were first discovered on November 8, 1895, by the German physicist Wilhelm Conrad Röntgen. The availability of this controllable source of X-rays created the field of radiography, the imaging of partly opaque objects with penetrating radiation. In contrast to other sources of ionizing radiation, X-rays are only produced as long as the X-ray tube is energized. X-ray tubes are also used in CT scanners, airport luggage scanners, X-ray crystallography, material and structure analysis, and

title: Grenz rays

text: Grenz rays Grenz rays are part of the electromagnetic spectrum comprising low energy (ultrasoft) X-rays. These were first investigated by Gustav Bucky in 1923 using a cathode vacuum tube with a lithium borate glass window, which he labeled Grenz rays as he believed that the biological effects resembled those of UV light and traditional X-rays and hence were on the border between the two ("Grenz" = border in German). These rays are also known as Bucky rays. Grenz rays are produced by specially calibrated X-ray machines generally operating in the 10 to 30 kV range to produce X-rays with HVL

title: Scorpius X-1

text: his urging, the company obtained a contract from the United States Air Force to explore the lunar surface prior to the launch of astronauts to the moon, and incidentally to perhaps see galactic sources of X-rays. Subsequently, Scorpius X-1 was discovered in 1962 by a team, under Riccardo Giacconi, who launched an Aerobee 150 sounding rocket carrying a highly sensitive soft X-ray detector designed by Frank Paolini. The rocket trajectory was slightly off course but still detected a significant emission of soft X-rays that were not coming from the moon. Thus fortuitously, and as first pointed out by Frank Paolini,

title: Grenz rays

text: palmoplantar pustulosis, neurodermatitis, pruritus ani and pruritus vulvae. They have been reported to be helpful for lichen planus, Grover's disease, Darier's disease, Hailey–Hailey disease and histiocytosis X. Grenz rays have also been used for treatment of actinic keratosis and Bowen's disease. Grenz rays Grenz rays are part of the electromagnetic spectrum comprising low energy (ultrasoft) X-rays. These were first investigated by Gustav Bucky in 1923 using a cathode vacuum tube with a lithium borate glass window, which he labeled Grenz rays as he believed that the biological effects resembled those of UV light and traditional X-rays and hence were on

title: X-ray astronomy detector

text: with radiation shorter than some arbitrary wavelength, such as 10 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 distinguished by their origin: X-rays are emitted by electrons outside the nucleus, while gamma rays are emitted by the nucleus. Although the more energetic X-rays, photons with an energy greater than 30 keV (4,800 aJ), can penetrate the air at least for distances of a few meters, the Earth's atmosphere is thick

title: Scorpius X-1

text: Scorpius X-1 Scorpius X-1 is an X-ray source located roughly 9000 light years away in the constellation Scorpius. Scorpius X-1 was the first extrasolar X-ray source discovered, and, aside from the Sun, it is the strongest apparent source of X-rays in the sky. The X-ray flux varies day-to-day, and is associated with an optically visible star, V818 Scorpii, that has an apparent magnitude which fluctuates between 12-13. The possible existence of cosmic soft X-rays was first proposed by Bruno Rossi, MIT Professor and Board Chairman of American Science and Engineering in Cambridge, Massachusetts to Martin Annis, President of AS&E. Following

title: X-ray astronomy

text: at such altitudes, much of the X-ray spectrum is still absorbed. X-rays with energies less than 35 keV (5,600 aJ) cannot reach balloons. On July 21, 1964, the Crab Nebula supernova remnant was discovered to be a hard X-ray (15 – 60 keV) source by a scintillation counter flown on a balloon launched from Palestine, Texas, USA. This was likely the first balloon-based detection of X-rays from a discrete cosmic X-ray source. The high-energy focusing telescope (HEFT) is a balloon-borne experiment to image astrophysical sources in the hard X-ray (20–100 keV) band. Its maiden flight took place in May 2005

title: X-ray generator

text: or oil recirculating systems. In medical imaging applications, an x-ray machine has a control console that is used by a radiologic technologist to select x-ray attributes suitable for the specific exam, a power supply that creates and produces the desired kVp (peak kilovoltage), mA (milliamperes, sometimes referred to as mAs which is actually mA multiplied by the desired exposure length) for the x-ray tube, and the x-ray tube itself. The discovery of X-rays came from experimenting with Crookes tubes, an early experimental electrical discharge tube invented by English physicist William Crookes around 1869-1875. In 1895, Wilhelm Röntgen discovered X-rays emanating

title: X-ray transient

text: sky for X-ray novae, flares, and other transient phenomena. It was a spinning satellite with pointing capability. SAS 3 was the first to discover X-rays from a highly magnetic WD binary system, AM Her, discovered X-rays from Algol and HZ 43, and surveyed the soft X-ray background (0.1-0.28 kev). Tenma was the second Japanese X-ray astronomy satellite launched on Feb 20 1983. Tenma carried GSFC detectors which had an improved energy resolution (by a factor of 2) compared to proportional counters and performed the first sensitive measurements of the iron spectral region for many astronomical objects. Energy Range: 0.1 keV

title: Free-orbit experiment with laser interferometry X-rays

text: stable state before each repetition of the experiment. Free-orbit experiment with laser interferometry X-rays The Free-orbit Experiment with Laser Interferometry X-Rays (FELIX) belongs to a category of experiments exploring whether macroscopic systems can be in superposition states. It was originally proposed by the physicist Roger Penrose in his book "The Road to Reality" specifically to prove whether unconventional decoherence processes such as gravitationally induced decoherence or spontaneous wave-function collapse of a quantum system occur. Later revised to take place as a tabletop experiment, if successful, it is estimated that a mass of roughly 10 atoms would have been superposed, approximately

text: Free-orbit experiment with laser interferometry X-rays The Free-orbit Experiment with Laser Interferometry X-Rays (FELIX) belongs to a category of experiments exploring whether macroscopic systems can be in superposition states. It was originally proposed by the physicist Roger Penrose in his book "The Road to Reality" specifically to prove whether unconventional decoherence processes such as gravitationally induced decoherence or spontaneous wave-function collapse of a quantum system occur. Later revised to take place as a tabletop experiment, if successful, it is estimated that a mass of roughly 10 atoms would have been superposed, approximately nine orders of magnitude more massive than any

title: Scorpius X-1

text: Scorpius X-1 became the first X-ray source discovered outside the Solar System. The angular resolution of the detector did not initially allow the position of Scorpius X-1 to be accurately determined. This led to suggestions that the source might be located near the Galactic center, but it was eventually realized that it lies in the constellation Scorpius. As the first discovered X-ray source in Scorpius, it received the designation Scorpius X-1. The Aerobee 150 rocket launched on June 12, 1962, detected the first X-rays from another celestial source (Scorpius X-1) at J1950 RA Dec . Sco X-1 is a LMXB

title: X-ray astronomy satellite

text: to discover X-rays from a highly magnetic WD binary system, AM Her, discovered X-rays from Algol and HZ 43, and surveyed the soft X-ray background (0.1-0.28 keV). To conduct experiments in X-ray astronomy and solar physics among others the Indian Space Research Organization (ISRO) built Aryabhata. It was launched by the Soviet Union on April 19, 1975, from Kapustin Yar. A power failure halted experiments after 4 days in orbit. Following on the success of Uhuru (SAS 1), NASA launched the Second Small Astronomy Satellite SAS 2. It was launched from the San Marco platform off the coast of Kenya,

title: X-ray crystallography

text: From the available data and physical reasoning, Barlow proposed several crystal structures in the 1880s that were validated later by X-ray crystallography; however, the available data were too scarce in the 1880s to accept his models as conclusive. Wilhelm Röntgen discovered X-rays in 1895, just as the studies of crystal symmetry were being concluded. Physicists were initially uncertain of the nature of X-rays, but soon suspected (correctly) that they were waves of electromagnetic radiation—in other words, another form of light. At that time, the wave model of light—specifically, the Maxwell theory of electromagnetic radiation—was well accepted among scientists, and experiments

title: X-ray tube

text: the waveform of the electrical source power (direct or pulsating). The heat produced in these devices is (in Joule) : In radiography voltage is usually expressed in formula_2 (thousands of volts peak), the effective current in mA and the time in seconds: w being the waveform ratio. With a full-wave rectification of a sine wave it equals formula_4, thus the practical unit: Historically, X-rays were discovered radiating from experimental discharge tubes called Crookes tubes invented by British physicist William Crookes and others. As the medical and other uses of X-rays became apparent, workshops began to manufacture specialized Crookes tubes to

title: X-ray

text: lower energy (and longer wavelength) are called "soft X-rays". Due to their penetrating ability, hard X-rays are widely used to image the inside of objects, e.g., in medical radiography and airport security. The term "X-ray" is metonymically used to refer to a radiographic image produced using this method, in addition to the method itself. Since the wavelengths of hard X-rays are similar to the size of atoms, they are also useful for determining crystal structures by X-ray crystallography. By contrast, soft X-rays are easily absorbed in air; the attenuation length of 600 eV (~2 nm) X-rays in water is less

title: Astrophysical X-ray source

text: can also interact with visible light emitted by the disk around the AGN or the black hole at its center. These photons accelerate the electrons, which then emit X- and gamma-radiation via Compton and inverse Compton scattering. On board the Compton Gamma Ray Observatory (CGRO) is the Burst and Transient Source Experiment (BATSE) which detects in the 20 keV to 8 MeV range. QSO 0836+7107 or 4C 71.07 was detected by BATSE as a source of soft gamma rays and hard X-rays. "What BATSE has discovered is that it can be a soft gamma-ray source", McCollough said. QSO 0836+7107 is

title: Cygnus X-1

text: in the millions of degrees. However, because X-ray emissions are blocked by the Earth's atmosphere, observation of celestial X-ray sources is not possible without lifting instruments to altitudes where the X-rays can penetrate. Cygnus X-1 was discovered using X-ray instruments that were carried aloft by a sounding rocket launched from White Sands Missile Range in New Mexico. As part of an ongoing effort to map these sources, a survey was conducted in 1964 using two Aerobee suborbital rockets. The rockets carried Geiger counters to measure X-ray emission in wavelength range 1– across an 8.4° section of the sky. These instruments

title: X-ray

text: had a limited life, and the restoration process was difficult to control. In 1904, John Ambrose Fleming invented the thermionic diode, the first kind of vacuum tube. This used a hot cathode that caused an electric current to flow in a vacuum. 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. 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 spectrum. He won the 1917 Nobel Prize in Physics

title: Cygnus X-1

text: black holes do not have magnetic poles. For example, the X-ray binary V 0332+53 was thought to be a possible black hole until pulsations were found. Cygnus X-1 has also never displayed X-ray bursts similar to those seen from neutron stars. Cygnus X-1 unpredictably changes between two X-ray states, although the X-rays may vary continuously between those states as well. In the most common state, the X-rays are "hard", which means that more of the X-rays have high energy. In the less common state, the X-rays are "soft", with more of the X-rays having lower energy. The soft state also

title: X-ray microscope

text: by the carbon atom (main element composing the living cell) and the oxygen atom (main element for water). Microfocus X-ray also achieves high magnification by projection. A microfocus X-ray tube produces X-rays from an extremely small focal spot (5µm down to 0.1µm). The X-rays are in the more conventional X-ray range (20 to 300 kV), and they are not re-focused. Early X-ray microscopes by Paul Kirkpatrick and Albert Baez used grazing incidence reflective X-ray optics to focus the X-rays, which grazed X-rays off parabolic curved mirrors at a very high angle of incidence. An alternative method of focusing X-rays is

title: X-ray vision

text: effect might be created via x-rays is unexplained (the x-rays from the viewer's eyes would need to bounce back to his eyes the same way as normal light reflects off objects and into the viewer's eyes: x-rays simply pass through an object and continue on their way. X-ray films are made as x-rays pass through an object and then through the x-ray film. The images seen on x-ray film are "shadows" of the objects the x-rays passed through on their way to the film). As depicted, x-ray vision is actually more of a form of the supposed psychic ability of

title: X-ray

text: were actually X-rays. In 1889 Ukrainian-born Ivan Pulyui, a lecturer in experimental physics at the Prague Polytechnic who since 1877 had been constructing various designs of gas-filled tubes to investigate their properties, published a paper on how sealed photographic plates became dark when exposed to the emanations from the tubes. Hermann von Helmholtz formulated mathematical equations for X-rays. He postulated a dispersion theory before Röntgen made his discovery and announcement. It was formed on the basis of the electromagnetic theory of light. However, he did not work with actual X-rays. In 1894 Nikola Tesla noticed damaged film in his lab

title: Health threat from cosmic rays

text: are highly ionizing forms of radiation, which produce distinct biological damage compared to X-rays and gamma-rays. Microscopic energy deposition from highly ionizing particles consists of a core radiation track due to direct ionizations by the particle and low energy electrons produced in ionization, and a penumbra of higher energy electrons that may extend hundreds of microns from the particles path in tissue. The core track produces extremely large clusters of ionizations within a few nanometres, which is qualitatively distinct from energy deposition by X-rays and gamma rays; hence human epidemiology data which only exists for these latter forms of radiation

title: Astrophysical X-ray source

text: X-rays by Saturn's atmosphere. The optical image is much brighter, and shows the beautiful ring structures, which were not detected in X-rays. Some of the detected X-rays, originating from solar system bodies other than the Sun, are produced by fluorescence. Scattered solar X-rays provide an additional component. In the Röntgensatellit (ROSAT) image of the Moon, pixel brightness corresponds to X-ray intensity. The bright lunar hemisphere shines in X-rays because it re-emits X-rays originating from the sun. The background sky has an X-ray glow in part due to the myriad of distant, powerful active galaxies, unresolved in the ROSAT picture. The

title: Grenz rays

text: less than 0.035 mm in aluminum. (HVL is half-value layer, and refers to a thickness of a given material that will cut the X-ray flux by 50%). Grenz rays are absorbed by air and therefore treatments must be given at fixed distances for which the machine has been calibrated. In human tissue Grenz rays have a half-value depth of 0.5 mm and are essentially absorbed within the first 2 mm of skin. The exact mechanism of action is unknown but it does have effects on the Langerhans cells in the epidermis. Grenz rays are indicated for treatment of eczema, psoriasis,

title: X-ray optics

text: reduce the absorption of x-rays in these stacks, materials with very low atomic number such as beryllium or lithium are typically used. Since the refractive index depends strongly on X-ray wavelength these lenses are highly chromatic and thus only suitable for monochromatic X-rays. The basic idea is to reflect a beam of X-rays from a surface and to measure the intensity of X-rays reflected in the specular direction (reflected angle equal to incident angle). It has been shown that a reflection off a parabolic mirror followed by a reflection off a hyperbolic mirror can lead to the focusing of X-rays.

title: X-ray binary

text: In LMXB systems the donor is less massive than the compact object, and can be on the main sequence, a degenerate dwarf (white dwarf), or an evolved star (red giant). Approximately two hundred LMXBs have been detected in the Milky Way, and of these, thirteen LMXBs have been discovered in globular clusters. The Chandra X-ray Observatory has revealed LMXBs in many distant galaxies. A typical low-mass X-ray binary emits almost all of its radiation in X-rays, and typically less than one percent in visible light, so they are among the brightest objects in the X-ray sky, but relatively faint in

title: X-ray microscope

text: X-ray microscope An X-ray microscope uses electromagnetic radiation in the soft X-ray band to produce magnified images of objects. Since X-rays penetrate most objects, there is no need to specially prepare them for X-ray microscopy observations. Unlike visible light, X-rays do not reflect or refract easily, and they are invisible to the human eye. Therefore, an X-ray microscope exposes film or uses a charge-coupled device (CCD) detector to detect X-rays that pass through the specimen. It is a contrast imaging technology using the difference in absorption of soft X-rays in the water window region (wavelengths: 2.34-4.4 nm, energies: 280-530 eV)

title: X-ray fluorescence

text: X-ray fluorescence X-ray fluorescence (XRF) is the emission of characteristic "secondary" (or fluorescent) X-rays from a material that has been excited by bombarding with high-energy X-rays or gamma rays. The phenomenon is widely used for elemental analysis and chemical analysis, particularly in the investigation of metals, glass, ceramics and building materials, and for research in geochemistry, forensic science, archaeology and art objects such as paintings and murals. When materials are exposed to short-wavelength X-rays or to gamma rays, ionization of their component atoms may take place. Ionization consists of the ejection of one or more electrons from the atom, and

title: X-ray crystallography

text: by Charles Glover Barkla showed that X-rays exhibited phenomena associated with electromagnetic waves, including transverse polarization and spectral lines akin to those observed in the visible wavelengths. Single-slit experiments in the laboratory of Arnold Sommerfeld suggested that X-rays had a wavelength of about 1 angstrom. However, X-rays are composed of photons, and thus are not only waves of electromagnetic radiation but also exhibit particle-like properties. Albert Einstein introduced the photon concept in 1905, but it was not broadly accepted until 1922, when Arthur Compton confirmed it by the scattering of X-rays from electrons. Therefore, these particle-like properties of X-rays, such

title: Industrial radiography

text: called Röntgen rays after the man who first described their properties in detail), a type of electromagnetic radiation. Soon after the discovery of X-rays, radioactivity was discovered. By using radioactive sources such as radium, far higher photon energies could be obtained than those from "normal" X-ray generators. Soon these found various applications, with one of the earliest users being Loughborough College. X-rays and gamma rays were put to use very early, before the dangers of ionizing radiation were discovered. After World War II new isotopes such as caesium-137, iridium-192 and cobalt-60 became available for industrial radiography, and the use of

title: X-ray

text: are several technologies being used for x-ray phase-contrast imaging, all utilizing different principles to convert phase variations in the x-rays emerging from an object into intensity variations. These include propagation-based phase contrast, talbot interferometry, refraction-enhanced imaging, and x-ray interferometry. These methods provide higher contrast compared to normal absorption-contrast x-ray imaging, making it possible to see smaller details. A disadvantage is that these methods require more sophisticated equipment, such as synchrotron or microfocus x-ray sources, X-ray optics, and high resolution x-ray detectors. X-rays with high photon energies (above 5–10 keV, below 0.2–0.1 nm wavelength) are called "hard X-rays", while those with

title: X-ray

text: computed tomography (CT), and to the growth in the use of nuclear medicine. Dosage due to dental X-rays varies significantly depending on the procedure and the technology (film or digital). Depending on the procedure and the technology, a single dental X-ray of a human results in an exposure of 0.5 to 4 mrem. A full mouth series of X-rays may result in an exposure of up to 6 (digital) to 18 (film) mrem, for a yearly average of up to 40 mrem. Financial incentives have been shown to have a significant impact on X-ray use with doctors who are paid

title: X-ray filter

text: unscathed. Therefore, it is possible to selectively fine tune which wavelengths of x-rays are present in a beam by matching materials with particular absorption characteristics to different X-ray source spectra. For example, a copper X-ray source may preferentially produce a beam of x-rays with wavelengths 154 and 139 picometres. Nickel has an absorption edge at 149 pm, between the two copper lines. Thus, using nickel as a filter for copper would result in the absorption of the slightly higher energy 139 pm x-rays, while letting the 154 pm rays through without a significant decrease in intensity. Thus, a copper X-ray

title: X-ray

text: were 46 experimenters taking up the technique in North America alone. The first use of X-rays under clinical conditions was by John Hall-Edwards in Birmingham, England on 11 January 1896, when he radiographed a needle stuck in the hand of an associate. On February 14, 1896 Hall-Edwards was also the first to use X-rays in a surgical operation. In early 1896, several weeks after Röntgen's discovery, Ivan Romanovich Tarkhanov irradiated frogs and insects with X-rays, concluding that the rays "not only photograph, but also affect the living function". The first medical X-ray made in the United States was obtained using

title: Cygnus X-1

text: swept across the sky as the rockets rotated, producing a map of closely spaced scans. As a result of these surveys, eight new sources of cosmic X-rays were discovered, including Cyg XR-1 (later Cyg X-1) in the constellation Cygnus the swan. The celestial coordinates of this source were estimated as right ascension 1953 and declination 34.6°. It was not associated with any especially prominent radio or optical source at that position. Seeing a need for longer duration studies, in 1963 Riccardo Giacconi and Herb Gursky proposed the first orbital satellite to study X-ray sources. NASA launched their Uhuru satellite in

title: Astrophysical X-ray source

text: Astrophysical X-ray source Astrophysical X-ray sources are astronomical objects with physical properties which result in the emission of X-rays. There are a number of types of astrophysical objects which emit X-rays, from galaxy clusters, through black holes in active galactic nuclei (AGN) to galactic objects such as supernova remnants, stars, and binary stars containing a white dwarf (cataclysmic variable stars and super soft X-ray sources), neutron star or black hole (X-ray binaries). Some solar system bodies emit X-rays, the most notable being the Moon, although most of the X-ray brightness of the Moon arises from reflected solar X-rays. A combination

title: Backscatter X-ray

text: would be given cancer but would die from other causes. There may not yet be evidence of hereditary effects of x-rays administered by backscatter scanners, but backscatter scanners use the same kind of x-ray photons as are produced in medical x-ray machines but expose the subject at a considerably lower dose, so it is possible that the results from medical radiology may be relevant, at least until a study is done of any effects specific to backscatter x-ray machines. Fathers exposed to medical diagnostic x-rays are more likely to have infants who contract leukemia, especially if exposure is closer to

title: X-ray generator

text: X-ray generator An X-ray generator is a device that produces X-rays. Together with an X-ray detector, it is commonly used in a variety of applications including medicine, fluorescence, electronic assembly inspection, and measurement of material thickness in manufacturing operations. In medical applications, X-ray generators are used by radiographers to acquire x-ray images of the internal structures (e.g., bones) of living organisms, and also in sterilization. An X-ray generator generally contains an X-ray tube to produce the X-rays. Possibly, radioisotopes can also be used to generate X-rays. An X-ray tube is a simple vacuum tube that contains a cathode, which directs

title: X-ray

text: a separate fee for each X-ray providing more X-rays. Other notable uses of X-rays include X-ray crystallography in which the pattern produced by the diffraction of X-rays through the closely spaced lattice of atoms in a crystal is recorded and then analysed to reveal the nature of that lattice. In the early 1990s, experiments were done in which layers a few atoms thick of two different materials were deposited in a Thue-Morse sequence. The resulting object was found to yield X-ray diffraction patterns. A related technique, fiber diffraction, was used by Rosalind Franklin to discover the double helical structure of

title: X-ray

text: tubes range from roughly 20 kV to 150 kV and thus the highest energies of the X-ray photons range from roughly 20 keV to 150 keV. Both of these X-ray production processes are inefficient, with only about one percent of the electrical energy used by the tube converted into X-rays, and thus most of the electric power consumed by the tube is released as waste heat. When producing a usable flux of X-rays, the X-ray tube must be designed to dissipate the excess heat. A specialized source of X-rays which is becoming widely used in research is synchrotron radiation, which

title: X-ray

text: for this discovery. In 1912, Max von Laue, Paul Knipping, and Walter Friedrich first observed the diffraction of X-rays by crystals. This discovery, along with the early work of Paul Peter Ewald, William Henry Bragg, and William Lawrence Bragg, gave birth to the field of X-ray crystallography. The Coolidge X-ray tube was invented during the following year by William D. Coolidge. It made possible the continuous emissions of X-rays. X-ray tubes similar to this are still in use in 2012. The use of X-rays for medical purposes (which developed into the field of radiation therapy) was pioneered by Major John

title: X-ray

text: and (according to Tesla) ozone. Many physicians claimed there were no effects from X-ray exposure at all. On August 3, 1905 at San Francisco, California, Elizabeth Fleischman, American X-ray pioneer, died from complications as a result of her work with X-rays. The many applications of X-rays immediately generated enormous interest. Workshops began making specialized versions of Crookes tubes for generating X-rays and these first-generation cold cathode or Crookes X-ray tubes were used until about 1920. Crookes tubes were unreliable. They had to contain a small quantity of gas (invariably air) as a current will not flow in such a tube

title: X-ray

text: "X-radiation" to signify an unknown type of radiation. Spelling of "X-ray(s)" in the English language includes the variants "x-ray(s)", "xray(s)", and "X ray(s)". Before their discovery in 1895 X-rays were just a type of unidentified radiation emanating from experimental discharge tubes. They were noticed by scientists investigating cathode rays produced by such tubes, which are energetic electron beams that were first observed in 1869. Many of the early Crookes tubes (invented around 1875) undoubtedly radiated X-rays, because early researchers noticed effects that were attributable to them, as detailed below. Crookes tubes created free electrons by ionization of the residual air

title: X-ray optics

text: X-ray optics X-ray optics is the branch of optics that manipulates X-rays instead of visible light. It deals with focusing and other ways of manipulating the X-ray beams for research techniques such as X-ray crystallography, X-ray fluorescence, small-angle X-ray scattering, X-ray microscopy, X-ray phase-contrast imaging, X-ray astronomy etc. Since X-rays and visible light are both electromagnetic waves they propagate in space in the same way, but because of the much higher frequency and photon energy of X-rays they interact with matter very differently. Visible light is easily redirected using lenses and mirrors, but because the refractive index of all materials

title: X-ray astronomy detector

text: the ultraviolet as ranging from ~10 nm to ~400 nm. That portion closest to X-rays is often referred to as the "extreme ultraviolet" (EUV or XUV). When an EUV photon is absorbed, photoelectrons and secondary electrons are generated by ionization, much like what happens when X-rays or electron beams are absorbed by matter. 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,

title: X-ray

text: than 1 micrometer. There is no consensus for a definition distinguishing between X-rays and gamma rays. One common practice is to distinguish between the two types of radiation based on their source: X-rays are emitted by electrons, while gamma rays are emitted by the atomic nucleus. This definition has several problems: other processes also can generate these high-energy photons, or sometimes the method of generation is not known. One common alternative is to distinguish X- and gamma radiation on the basis of wavelength (or, equivalently, frequency or photon energy), with radiation shorter than some arbitrary wavelength, such as 10 m

title: X-ray

text: medical use when he made a picture of his wife's hand on a photographic plate formed due to X-rays. The photograph of his wife's hand was the first photograph of a human body part using X-rays. When she saw the picture, she said "I have seen my death." The discovery of X-rays stimulated a veritable sensation. Röntgen's biographer Otto Glasser estimated that, in 1896 alone, as many as 49 essays and 1044 articles about the new rays were published. This was probably a conservative estimate, if one considers that nearly every paper around the world extensively reported about the new

title: X-ray crystallography

text: elastic X-ray scattering include powder diffraction, Small-Angle X-ray Scattering (SAXS) and several types of X-ray fiber diffraction, which was used by Rosalind Franklin in determining the double-helix structure of DNA. In general, single-crystal X-ray diffraction offers more structural information than these other techniques; however, it requires a sufficiently large and regular crystal, which is not always available. These scattering methods generally use "monochromatic" X-rays, which are restricted to a single wavelength with minor deviations. A broad spectrum of X-rays (that is, a blend of X-rays with different wavelengths) can also be used to carry out X-ray diffraction, a technique known

title: X-ray

text: produced. X-rays can be generated by an X-ray tube, a vacuum tube that uses a high voltage to accelerate the electrons released by a hot cathode to a high velocity. The high velocity electrons collide with a metal target, the anode, creating the X-rays. In medical X-ray tubes the target is usually tungsten or a more crack-resistant alloy of rhenium (5%) and tungsten (95%), but sometimes molybdenum for more specialized applications, such as when softer X-rays are needed as in mammography. In crystallography, a copper target is most common, with cobalt often being used when fluorescence from iron content in

title: X-ray

text: wavelength of the X-ray. The scattered photon can go in any direction, but a direction similar to the original direction is more likely, especially for high-energy X-rays. The probability for different scattering angles are described by the Klein–Nishina formula. The transferred energy can be directly obtained from the scattering angle from the conservation of energy and momentum. Rayleigh scattering is the dominant elastic scattering mechanism in the X-ray regime. Inelastic forward scattering gives rise to the refractive index, which for X-rays is only slightly below 1. Whenever charged particles (electrons or ions) of sufficient energy hit a material, X-rays are

title: X-ray

text: for the application so as to give sufficient transmission through the object and at the same time provide good contrast in the image. X-rays have much shorter wavelengths than visible light, which makes it possible to probe structures much smaller than can be seen using a normal microscope. This property is used in X-ray microscopy to acquire high resolution images, and also in X-ray crystallography to determine the positions of atoms in crystals. X-rays interact with matter in three main ways, through photoabsorption, Compton scattering, and Rayleigh scattering. The strength of these interactions depends on the energy of the X-rays

title: Astrophysical X-ray source

text: Borealis. It is one of the most massive objects in the universe. From the Chandra X-ray analysis of the Antennae Galaxies rich deposits of neon, magnesium, and silicon were discovered. These elements are among those that form the building blocks for habitable planets. The clouds imaged contain magnesium and silicon at 16 and 24 times respectively, the abundance in the Sun. The jet exhibited in X-rays coming from PKS 1127-145 is likely due to the collision of a beam of high-energy electrons with microwave photons. The Draco nebula (a soft X-ray shadow) is outlined by contours and is blue-black in

title: X-ray crystallography

text: single-crystal X-ray diffractometers. X-ray crystallography is a form of elastic scattering; the outgoing X-rays have the same energy, and thus same wavelength, as the incoming X-rays, only with altered direction. By contrast, "inelastic scattering" occurs when energy is transferred from the incoming X-ray to the crystal, e.g., by exciting an inner-shell electron to a higher energy level. Such inelastic scattering reduces the energy (or increases the wavelength) of the outgoing beam. Inelastic scattering is useful for probing such excitations of matter, but not in determining the distribution of scatterers within the matter, which is the goal of X-ray crystallography. X-rays

title: X-ray photoelectron spectroscopy

text: X-ray is roughly 0.70 eV, which, in effect is the ultimate energy resolution of a system using non-monochromatic X-rays. Non-monochromatic X-ray sources do not use any crystals to diffract the X-rays which allows all primary X-rays lines and the full range of high-energy Bremsstrahlung X-rays (1–12 keV) to reach the surface. The ultimate energy resolution (FWHM) when using a non-monochromatic Mg "K"-alpha source is 0.9–1.0 eV, which includes some contribution from spectrometer-induced broadening. XPS is routinely used to determine: The ability to produce chemical state information (as distinguished from merely elemental information) from the topmost few nm of any surface

title: X-ray astronomy detector

text: X-ray astronomy detector X-ray astronomy detectors are instruments that detect X-rays for use in the study of X-ray astronomy. X-ray astronomy is an observational branch of astronomy which deals with the study of X-ray emission from celestial objects. X-radiation is absorbed by the Earth's atmosphere, so instruments to detect X-rays must be taken to high altitude by balloons, sounding rockets, and satellites. X-ray astronomy is part of space science. "X-ray astronomy detectors" have been designed and configured primarily for energy and occasionally for wavelength detection using a variety of techniques usually limited to the technology of the time. X-rays span

title: X-ray optics

text: The array is tapered so that one end of the capillaries points at the X-ray source and the other at the sample. Polycapillary optics are achromatic and thus suitable for scanning fluorescence imaging and other applications where a broad X-ray spectrum is useful. They collect X-rays efficiently for photon energies of 0.1 to 30 keV and can achieve gains of 100 to 10000 in flux over using a pinhole at 100 mm from the X-ray source. Since only X-rays entering the capillaries within a very narrow angle will be totally internally reflected, only X-rays coming from a small spot will

title: X-ray crystallography

text: as their ionization of gases, caused William Henry Bragg to argue in 1907 that X-rays were "not" electromagnetic radiation. Nevertheless, Bragg's view was not broadly accepted and the observation of X-ray diffraction by Max von Laue in 1912 confirmed for most scientists that X-rays were a form of electromagnetic radiation. Crystals are regular arrays of atoms, and X-rays can be considered waves of electromagnetic radiation. Atoms scatter X-ray waves, primarily through the atoms' electrons. Just as an ocean wave striking a lighthouse produces secondary circular waves emanating from the lighthouse, so an X-ray striking an electron produces secondary spherical waves

title: X-ray microscope

text: world's first soft x-ray microscope designed for biological and biomedical research. This new instrument, XM-2 was designed and built by scientists from the National Center for X-ray Tomography. XM-2 is capable of producing 3-dimensional tomograms of cells. Sources of soft X-rays suitable for microscopy, such as synchrotron radiation sources, have fairly low brightness of the required wavelengths, so an alternative method of image formation is scanning transmission soft X-ray microscopy. Here the X-rays are focused to a point and the sample is mechanically scanned through the produced focal spot. At each point the transmitted X-rays are recorded with a detector

title: X-ray binary

text: X-ray binary X-ray binaries are a class of binary stars that are luminous in X-rays. The X-rays are produced by matter falling from one component, called the "donor" (usually a relatively normal star), to the other component, called the "accretor", which is very compact: a neutron star or black hole. The infalling matter releases gravitational potential energy, up to several tenths of its rest mass, as X-rays. (Hydrogen fusion releases only about 0.7 percent of rest mass.) The lifetime and the mass-transfer rate in an X-ray binary depends on the evolutionary status of the donor star, the mass ratio between

title: Nike-X

text: the sophistication or hardening of the MAR. This led to the Perimeter Acquisition Radar (PAR), which would operate cheaper electronics at VHF frequencies. The high-altitude explosions that had caused so much concern for Nike Zeus due to blackout had been further studied in the early 1960s and led to a new possibility for missile defense. When a nuclear warhead explodes in a dense atmosphere, its initial high-energy X-rays ionize the air, blocking other X-rays. In the highest layers of the atmosphere, there is too little gas for this to occur, and the X-rays can travel long distances. Sufficient X-ray exposure

title: Seven rays

text: Trinity. The inscription reads: "Radiating from this symbol are seven rays of light representing the seven gifts of the Holy Ghost." During the 12th century, Saint Norbert of Xanten, founder of the Order of Canons Regular of Prémontré, discovered the spot where the relics of Saint Ursula and her companions of Saint Gereon and of other martyrs lay hidden while in a dream. In the dream that led him to this location, he was guided by "the seven rays of light... surrounding the head of the crucified Redeemer." The Annunciation is an oil painting by Early Netherlandish master Jan van

title: Cygnus X-1

text: the brightest persistent source of hard X-rays—those with energies from about 30 up to several hundred keV—in the sky. The X-rays are produced as lower energy photons in the thin inner accretion disk, then given more energy through Compton scattering with very high temperature electrons in a geometrically thicker, but nearly transparent corona enveloping it, as well as by some further reflection from the surface of the thin disk. An alternative possibility is that the X-rays may be Compton scattered by the base of a jet instead of a disk corona. The X-ray emission from Cygnus X-1 can vary in

title: X-ray detector

text: film allows a lower dose to the patient, because the screen(s) improve the efficiency of x-ray detection, making more activation of the film from the same amount of x-rays, or the same activation of the film from a smaller amount of x-rays. Phosphor plate radiography is a method of recording X-rays using photostimulated luminescence (PSL), pioneered by Fuji in the 1980s. A photostimulable phosphor plate (PSP) is used in place of the photographic plate. After the plate is X-rayed, excited electrons in the phosphor material remain 'trapped' in 'colour centres' in the crystal lattice until stimulated by a laser beam

title: X-ray binary

text: which atomic emission lines are visible from both jets; GRS 1915+105, with an especially high jet velocity and the very bright Cygnus X-1, detected up to the High Energy gamma rays (E > 60 MeV). Extremely high energies of particles emitting in the VHE band might be explained by several mechanisms of particle acceleration (see Fermi acceleration and Centrifugal mechanism of acceleration). X-ray binary X-ray binaries are a class of binary stars that are luminous in X-rays. The X-rays are produced by matter falling from one component, called the "donor" (usually a relatively normal star), to the other component, called

title: X-ray lithography

text: as with a synchrotron radiation, elementary collimating mirrors or diffractive lenses are used in the place of the refractive lenses used in optics. The X-rays illuminate a mask placed in proximity of a resist-coated wafer. The X-rays are broadband, typically from a compact synchrotron radiation source, allowing rapid exposure. Deep X-ray lithography (DXRL) uses yet shorter wavelengths on the order of and modified procedures such as the LIGA process, to fabricate deep and even three-dimensional structures. The mask consists of an X-ray absorber, typically of gold or compounds of tantalum or tungsten, on a membrane that is transparent to X-rays,

title: X-ray filter

text: source with a nickel filter can produce a nearly monochromatic X-ray beam with photons of mostly 154 pm. For medical purposes, X-ray filters are used to selectively attenuate, or block out, low-energy rays during x-ray imaging (radiography). Low energy x-rays (less than 30 keV) contribute little to the resultant image as they are heavily absorbed by the patient's soft tissues (particularly the skin). Additionally, this absorption adds to the risk of stochastic (e.g. cancer) or non stochastic radiation effects (e.g. tissue reactions) in the patient. Thus, it is favorable to remove these low energy X-rays from the incident light beam.

title: X-ray

text: DNA. X-ray astronomy, which is an observational branch of astronomy, which deals with the study of X-ray emission from celestial objects. X-ray microscopic analysis, which uses electromagnetic radiation in the soft X-ray band to produce images of very small objects. X-ray fluorescence, a technique in which X-rays are generated within a specimen and detected. The outgoing energy of the X-ray can be used to identify the composition of the sample. Industrial radiography uses X-rays for inspection of industrial parts, particularly welds. Authentication and quality control, X-ray is used for authentication and quality control of packaged items. Industrial CT (computed tomography)

title: Electromagnetic radiation

text: waves, and produced and characterized what were later termed radio waves and microwaves. Wilhelm Röntgen discovered and named X-rays. After experimenting with high voltages applied to an evacuated tube on 8 November 1895, he noticed a fluorescence on a nearby plate of coated glass. In one month, he discovered X-rays' main properties. The last portion of the EM spectrum to be discovered was associated with radioactivity. Henri Becquerel found that uranium salts caused fogging of an unexposed photographic plate through a covering paper in a manner similar to X-rays, and Marie Curie discovered that only certain elements gave off these

title: X-ray

text: in the tube by a high DC voltage of anywhere between a few kilovolts and 100 kV. This voltage accelerated the electrons coming from the cathode to a high enough velocity that they created X-rays when they struck the anode or the glass wall of the tube. The earliest experimenter thought to have (unknowingly) produced X-rays was actuary William Morgan. In 1785 he presented a paper to the Royal Society of London describing the effects of passing electrical currents through a partially evacuated glass tube, producing a glow created by X-rays. This work was further explored by Humphry Davy and

title: Micro-X-ray fluorescence

text: X-rays without disturbing the sample. It was discovered recently by scientists at the Los Alamos National Laboratory. The newly discovered technique was then first revealed at the 229th national meeting of the American Chemical Society (March, 2005). This new discovery could prove to be very beneficial to the law enforcement world, because it is expected that "µXRF" will be able to detect the most complex molecules in fingerprints. Michael Bernstein of the American Chemical Society describes how the process works "Salts such as sodium chloride and potassium chloride excreted in sweat are sometimes present in detectable quantities in fingerprints. Using

title: Soft x-ray microscopy

text: carbon atom (main element composing the living cell) and the oxygen atom (main element for water). Early X-ray microscopes by Paul Kirkpatrick and Albert Baez used grazing incidence reflective optics to focus the X-rays, which grazed X-rays off parabolic curved mirrors at a very high angle of incidence. An alternative method of focusing X-rays is to use a tiny fresnel zone plate of concentric gold or nickel rings on a silicon dioxide substrate. Sir Lawrence Bragg produced some of the first usable X-ray images with his apparatus in the late 1940s. In the 1950s Newberry produced a shadow X-ray microscope

title: Astrophysical X-ray source

text: X-rays was taken in March 1996, with the orbiting Polar satellite. Energetically charged particles from the Sun cause aurora and energize electrons in the Earth's magnetosphere. These electrons move along the Earth's magnetic field and eventually strike the Earth's ionosphere, producing the X-ray emission. Astrophysical X-ray source Astrophysical X-ray sources are astronomical objects with physical properties which result in the emission of X-rays. There are a number of types of astrophysical objects which emit X-rays, from galaxy clusters, through black holes in active galactic nuclei (AGN) to galactic objects such as supernova remnants, stars, and binary stars containing a white

title: X-ray astronomy satellite

text: continue to operate. For example, the Chandra X-ray Observatory has been operational for more than fifteen years. Satellites in use today include the XMM-Newton observatory (low to mid energy X-rays 0.1-15 keV) and the INTEGRAL satellite (high energy X-rays 15-60 keV). Both were launched by the European Space Agency. NASA has launched the Swift and Chandra observatories. One of the instruments on Swift is the Swift X-Ray Telescope (XRT). The GOES 14 spacecraft carries on board a Solar X-ray Imager to monitor the Sun's X-rays for the early detection of solar flares, coronal mass ejections, and other phenomena that impact

title: X-ray

text: is generated by particle accelerators. Its unique features are X-ray outputs many orders of magnitude greater than those of X-ray tubes, wide X-ray spectra, excellent collimation, and linear polarization. Short nanosecond bursts of X-rays peaking at 15-keV in energy may be reliably produced by peeling pressure-sensitive adhesive tape from its backing in a moderate vacuum. This is likely to be the result of recombination of electrical charges produced by triboelectric charging. The intensity of X-ray triboluminescence is sufficient for it to be used as a source for X-ray imaging. X-rays can also be produced by fast protons or other positive

title: X unit

text: X unit The x unit (symbol xu) is a unit of length approximately equal to 0.1 pm (10 m). It is used to quote the wavelength of X-rays and gamma rays. Originally defined by the Swedish physicist Manne Siegbahn (1886–1978) in 1925, the x unit could not at that time be measured directly; the definition was instead made in terms of the spacing between planes of the calcite crystals used in the measuring apparatus. One x unit was set at of the spacing of the (200) planes of calcite at 18 °C. In modern usage, there are two separate x

title: X-ray tube

text: a thin platinum face) target at the center generating X-rays. The anode surface was angled so that the X-rays would radiate through the side of the tube. The cathode was concave so that the electrons were focused on a small (~1 mm) spot on the anode, approximating a point source of X-rays, which resulted in sharper images. The tube had a third electrode, an anticathode connected to the anode. It improved the X-ray output, but the method by which it achieved this is not understood. A more common arrangement used a copper plate anticathode (similar in construction to the cathode)

title: X-ray detector

text: is created that can be swiftly converted to a voltage and then a digital signal, which is interpreted by a computer to produce a digital image. Although silicon has outstanding electronic properties, it is not a particularly good absorber of X-ray photons. For this reason, X-rays first impinge upon scintillators made from such materials as gadolinium oxysulfide or caesium iodide. The scintillator absorbs the X-rays and converts them into visible light photons that then pass onto the photodiode array. X-rays going through a gas will ionize it, producing positive ions and free electrons. An incoming photon will create a number