Although exposure to ionizing radiation carries a risk, it is impossible to completely avoid exposure. Radiation has always been present in the environment and in our bodies. We can, however, avoid undue exposure. Although people cannot sense ionizing radiation, there is a range of simple, sensitive instruments capable of detecting minute amounts of radiation from natural and man-made sources. Dosimeters measure an absolute dose received over a period of time. Ion-chamber dosimeters resemble pens, and can be clipped to one's cl ...

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Ionizing radiation, Ionizing radiation - Types of radiation, Ionizing radiation - Example: Electromagnetic radiation, Ionizing radiation - Sources of ionizing radiation, Ionizing radiation - Natural background radiation, Ionizing radiation - Man-made radiation sources, Ionizing radiation - The effects of ionizing radiation on animals, Ionizing radiation - Chronic radiation exposure, Ionizing radiation - Acute radiation exposure, Ionizing radiation - Radiation levels, Ionizing radiation - Minimizing health effects of ionizing radiation

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Cherenkov radiation is used to detect high-energy charged particles. In pool-type nuclear reactors, the intensity of Cherenkov radiation is related to the frequency of the fission events that produce high-energy electrons, and hence is a measure of the intensity of the reaction. Cherenkov radiation is also used to characterize the remaining radioactivity of spent fuel rods. When a high-energy cosmic ray interacts with the Earth's atmosphere, it may produce an electron-positron pair with enormous velocities. The Cherenkov radiation fro ...

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Cherenkov radiation, Cherenkov radiation - Physical origin, Cherenkov radiation - Characteristics, Cherenkov radiation - Uses, Cherenkov radiation - Notes

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Intuitively, the overall intensity of Cherenkov radiation is proportional to the velocity of the inciting charged particle and to the number of such particles. Unlike fluorescence or emission spectra that have characteristic spectral peaks, Cherenkov radiation is continuous. The relative intensity of one frequency is proportional to the frequency. That is, higher frequencies (shorter wavelengths) are more intense in Cherenkov radiation. This is why visible Cherenkov radiation is observed to be brilliant blue. In fact, most Cherenkov radiatio ...

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Cherenkov radiation, Cherenkov radiation - Physical origin, Cherenkov radiation - Characteristics, Cherenkov radiation - Uses, Cherenkov radiation - Notes

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Synchrotron radiation is also generated by astronomical structures and motions, typically where relativistic electrons spiral (and hence change velocity) through magnetic fields. It was first detected in 1956 by Geoffrey R. Burbidge, in a jet emitted by M87 [2], who saw it as confirmation of a prediction by Iosif S. Shklovskii in 1953, but which had been predicted several years earlier by Hannes Alfvén and Nicolai Herlofson [3] in 1950. Supermassive black holes have been suggested for producing synchrot ...

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Synchrotron radiation, Synchrotron radiation - Synchrotron radiation from storage rings, Synchrotron radiation - Synchrotron radiation in astronomy

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The radiation from natural and man-made radiation sources are identical in their nature and their effects. These materials are distributed in the environment, and in our bodies, according to the chemical properties of the elements. The Nuclear Regulatory Commission, the Environmental Protection Agency, and other U.S. and international agencies, require that licensees limit radiation exposure to individual members of the public to 100 mrem (1 mSv) per year, and limit occupational radiation exposure to adults working with radioactive ma ...

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Background radiation, Background radiation - Natural background radiation, Background radiation - Cosmic radiation, Background radiation - Terrestrial sources, Background radiation - Radon, Background radiation - Man-made background radiation, Background radiation - Man-made radiation sources, Background radiation - Other usage

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It may be shown by electromagnetic theory, by quantum theory, or by thermodynamics, making no assumptions as to the nature of the radiation, that the pressure against a surface exposed in a space traversed by radiation uniformly in all directions is equal to 1/3 the total radiant energy per unit volume within that space. For black body radiation, in equilibrium with the exposed surface, the energy density is, in accordance with the Stefan-Boltzmann law, equal to σT4/3c; in which σ is the Stefan-Boltzm ...

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Radiation pressure, Radiation pressure - Discovery, Radiation pressure - Theory, Radiation pressure - In interplanetary space, Radiation pressure - In stellar interiors, Radiation pressure - Solar sails, Radiation pressure - Radiation pressure in acoustics

Read more here: » Radiation pressure: Encyclopedia II - Radiation pressure - Theory

Three main divisions of radiotherapy are external beam radiotherapy (XBRT) or teletherapy, brachytherapy or sealed source radiotherapy and unsealed source radiotherapy. The differences relate to the position of the radiation source; external is outside the body, while sealed and unsealed source radiotherapy has radioactive material delivered internally. Brachytherapy sealed sources are usually extracted later, while unsealed sources may be administered by injection or ingestion. Proton therapy is a special case of external beam radiotherapy where the particles are protons. Roughly half of the ...

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Radiation therapy, Radiation therapy - Application, Radiation therapy - Side Effects, Radiation therapy - Acute Side Effects, Radiation therapy - Medium and Long-Term Side Effects, Radiation therapy - Dosage, Radiation therapy - Fractionation Schedules, Radiation therapy - How It Works, Radiation therapy - Kinds of Radiation Therapy, Radiation therapy - Conventional External Beam Radiotherapy, Radiation therapy - Virtual Simulation 3-Dimensional Conformal Radiotherapy and Intensity-Modulated Radiotherapy

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Radiation hardening - Fundamental mechanisms. Two fundamental damage mechanisms take place: Lattice displacement, caused by neutrons, protons, alpha particles, heavy ions, and very high energy gamma photons. They change the arrangement of the atoms in the lattice, creating lasting damage, and increasing the number of recombination centers, depleting the minority carriers and worsening the analog properties of the affected semiconductor junctions. Counterintuitively, higher doses over short tim ...

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Radiation hardening, Radiation hardening - Major radiation damage sources, Radiation hardening - Radiation effects on electronics, Radiation hardening - Fundamental mechanisms, Radiation hardening - Resultant effects, Radiation hardening - Digital damage: SEE, Radiation hardening - Radiation-hardening techniques, Radiation hardening - Examples of rad-hard computers

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Every above-ground nuclear detonation scatters a certain amount of radioactive contamination. Some of this contamination is local, rendering the immediate surroundings highly radioactive, while some of it is carried longer distances as nuclear fallout; some of this material is dispersed worldwide. Nuclear reactors may also release a certain amount of radioactive contamination. Under normal circumstances, a modern nuclear reactor releases miniscule amounts of radioactive contamination. However, reprocessing plants released waste, including pl ...

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Background radiation, Background radiation - Natural background radiation, Background radiation - Cosmic radiation, Background radiation - Terrestrial sources, Background radiation - Radon, Background radiation - Man-made background radiation, Background radiation - Man-made radiation sources, Background radiation - Other usage

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Radiotherapy is commonly used for the treatment of malignant tumors (cancer.) It may be used as the primary therapy. It is also common to combine radiotherapy with surgery and/or chemotherapy and/or hormone therapy. Most common cancer types can be treated with radiotherapy in some way. The precise treatment intent (radical, adjuvant, or palliative) will depend on the tumour type, location, and sta ...

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Radiation therapy, Radiation therapy - Application, Radiation therapy - Side Effects, Radiation therapy - Acute Side Effects, Radiation therapy - Medium and Long-Term Side Effects, Radiation therapy - Dosage, Radiation therapy - Fractionation Schedules, Radiation therapy - How It Works, Radiation therapy - Kinds of Radiation Therapy, Radiation therapy - Conventional External Beam Radiotherapy, Radiation therapy - Virtual Simulation 3-Dimensional Conformal Radiotherapy and Intensity-Modulated Radiotherapy

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Radiation therapy, like drugs, has biological effects. It is therefore useful to distinguish the total dose from the fractionation schedule. Radiation therapy is usually given daily, the dose depends primarily on tumor type, but many other factors such as whether radiation is given alone or with chemotherapy, before or after surgery, the success of surgery and its findings and many other reasons that are considered by the treating doctor (known as a radiation oncologist). For Radical (curative) cases the typical dose for a solid epithelial t ...

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Radiation therapy, Radiation therapy - Application, Radiation therapy - Side Effects, Radiation therapy - Acute Side Effects, Radiation therapy - Medium and Long-Term Side Effects, Radiation therapy - Dosage, Radiation therapy - Fractionation Schedules, Radiation therapy - How It Works, Radiation therapy - Kinds of Radiation Therapy, Radiation therapy - Conventional External Beam Radiotherapy, Radiation therapy - Virtual Simulation 3-Dimensional Conformal Radiotherapy and Intensity-Modulated Radiotherapy

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Electromagnetic radiation - Theory. Electromagnetic waves of much lower frequency than visible light were predicted by Maxwell's equations and subsequently discovered by Heinrich Hertz. Maxwell derived a wave form of the electric and magnetic equations which made explicit the wave nature of the electric and magnetic fields. These equations displayed the symmetry of the fields. According to the theory, a time-varying electric field generates a magnetic field and vice versa. Thus, an oscillating elect ...

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Electromagnetic radiation, Electromagnetic radiation - Physics, Electromagnetic radiation - Theory, Electromagnetic radiation - Properties, Electromagnetic radiation - Wave model, Electromagnetic radiation - Particle model, Electromagnetic radiation - Speed of propagation, Electromagnetic radiation - Electromagnetic spectrum, Electromagnetic radiation - Light, Electromagnetic radiation - Radio waves, Electromagnetic radiation - Derivation

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Electromagnetic waves as a general phenomenon were predicted by the classical laws of electricity and magnetism, known as Maxwell's equations. If you inspect Maxwell's equations without sources (charges or currents) then you will find that, along with the possibility of nothing happening, the theory will also admit nontrivial solutions of changing electric and magnetic fields. (For symbol definitions see magnetic field.) is a solution, but there might be other solutions as well. Let us employ a us ...

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Electromagnetic radiation, Electromagnetic radiation - Physics, Electromagnetic radiation - Theory, Electromagnetic radiation - Properties, Electromagnetic radiation - Wave model, Electromagnetic radiation - Particle model, Electromagnetic radiation - Speed of propagation, Electromagnetic radiation - Electromagnetic spectrum, Electromagnetic radiation - Light, Electromagnetic radiation - Radio waves, Electromagnetic radiation - Derivation

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Synchrotron radiation is characterized by: High brightness and high intensity, many orders of magnitude more than with x-rays produced in conventional x-ray tubes High brilliance, exceeding other natural and artificial light sources by many orders of magnitude: 3rd generation sources typically have a brilliance larger than 1018photons / s / mm2 / mrad2 / 0.1%B ...

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Synchrotron radiation, Synchrotron radiation - Synchrotron radiation from storage rings, Synchrotron radiation - Synchrotron radiation in astronomy

Read more here: » Synchrotron radiation: Encyclopedia II - Synchrotron radiation - Synchrotron radiation from storage rings

Although the "classical" and "quantum" descriptions of the overall statistical characteristics of the emitted radiation agree, the nature of the specific information encoded within that outgoing radiation, and how it relates to information inside the hole, is still a matter of dispute in the research community. If classical radiation effects are completely responsible for Hawking radiation, then this radiation will originate inside the horizon – there will be a theoretical statistical correlation between information that enter ...

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Acoustic Hawking radiation, Acoustic Hawking radiation - Gravitational analogues, Acoustic Hawking radiation - Analogy vs identity, Acoustic Hawking radiation - Types of non-gravitational Hawking radiation, Acoustic Hawking radiation - Overlap of quantum and classical behaviour, Acoustic Hawking radiation - The membrane paradigm, Acoustic Hawking radiation - Controversy: Identity of radiated information, Acoustic Hawking radiation - Some recent mainstream views paraphrased, Acoustic Hawking radiation - Historical dates

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Like infrared radiation or microwaves, these waves usually travel in line of sight. Terahertz radiation is non-ionizing and shares with microwaves the capability to penetrate a wide variety of non-conducting materials. They can pass through clothing, paper, cardboard, wood, masonry, plastic and ceramics. They can also penetrate fog and clouds but cannot penetrate metal or water. The Earth's atmosphere is a strong absorber of terahertz radiation, so the range of terahertz radiation is quite short, limiting its usefulness. In addition, producing and detecting coherent terahertz ra ...

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Terahertz radiation, Terahertz radiation - Introduction, Terahertz radiation - Sources, Terahertz radiation - Theoretical and technological uses under development

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Radiation Control:

An APK talent for speeding up and slowing down the decay rates of radioactive materials.

(See also: Radiation Control, Pagan, Paganism, Pagan Dictionary)

List of nuclear and radiation accidents - Criticality accidents. Criticality accidents and power excursions in nuclear reactors, for example the Chernobyl accident. In a smaller scale accident at Sarov a man working with highly enriched uranium was irradiated while attempting an experiment involving a sphere of fissile material. The Sarov accident is interesting because the system remained critical for many days before it could be stopped. This is an example of a limited scope accident where only a few people can ...

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List of nuclear and radiation accidents, List of nuclear and radiation accidents - Accident types, List of nuclear and radiation accidents - Criticality accidents, List of nuclear and radiation accidents - Decay heat, List of nuclear and radiation accidents - Transport, List of nuclear and radiation accidents - Equipment failure, List of nuclear and radiation accidents - Human error, List of nuclear and radiation accidents - Lost source, List of nuclear and radiation accidents - Others, List of nuclear and radiation accidents - Civilian nuclear accidents, List of nuclear and radiation accidents - Civilian radiation accidents, List of nuclear and radiation accidents - Military nuclear accidents

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Scientists are eager to directly measure gravitational waves from astronomical sources, as they can probe phenomena that are difficult or impossible to study with electromagnetic radiation. For instance, although a black hole emits no visible radiation in the way that a regular star does, gravitational waves can be emitted when an object falls into a black hole, or when two black holes collide. If the inspiraling mass is significantly smaller than the central black hole, the emitted gravitational waves may, at least in some circumstances, al ...

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Gravitational radiation, Gravitational radiation - Overview, Gravitational radiation - The Nature of Gravitational Waves, Gravitational radiation - Sources of Gravitational Waves, Gravitational radiation - Detection, Gravitational radiation - Einstein@Home, Gravitational radiation - Prospects, Gravitational radiation - Derivation, Gravitational radiation - Perturbation of Flat Space-time, Gravitational radiation - Perturbation with Sources, Gravitational radiation - Far from Source Approximation, Gravitational radiation - Perturbative versus Exact, Gravitational radiation - Gravitational waves transmit energy

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Black holes are sites of immense gravitational attraction into which surrounding matter is drawn by gravitational forces. Classically, the gravitation is so powerful that nothing, not even radiation, can escape from the black hole. However, by doing a calculation in the framework of quantum field theory in curved spacetimes, Hawking showed quantum effects allow black holes to emit radiation in a thermal spectrum. Physical insight on the process may be gained by imagining that (particle-antiparticle) radiation is emitted from just beyo ...

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Hawking radiation, Hawking radiation - Overview, Hawking radiation - Example, Hawking radiation - Problems with the theory, Hawking radiation - Emission process, Hawking radiation - Black hole evaporation

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Russell Alan Hulse and Joseph Hooton Taylor Jr. were awarded the Nobel Prize in Physics in 1993 for their observations of a remarkable binary pulsar, PSR B1913+16. According to general relativity, this system should emit gravitational radiation which carries off energy at a specific rate, which should in turn cause the orbit to decay at a rate of roughly 7 mm per day. This prediction agrees with the observations of Hulse and Taylor. But to directly detect gravitational waves you would have to look for any motion they cause. Typic ...

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Gravitational radiation, Gravitational radiation - Overview, Gravitational radiation - The Nature of Gravitational Waves, Gravitational radiation - Sources of Gravitational Waves, Gravitational radiation - Detection, Gravitational radiation - Einstein@Home, Gravitational radiation - Prospects, Gravitational radiation - Derivation, Gravitational radiation - Perturbation of Flat Space-time, Gravitational radiation - Perturbation with Sources, Gravitational radiation - Far from Source Approximation, Gravitational radiation - Perturbative versus Exact, Gravitational radiation - Gravitational waves transmit energy

Read more here: » Gravitational radiation: Encyclopedia II - Gravitational radiation - Detection