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Encyclopedia > Gamma ray
Nuclear physics
Radioactive decay
Nuclear fission
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Gamma rays (denoted as γ) are a form of electromagnetic radiation or light emission of frequencies produced by sub-atomic particle interactions, such as electron-positron annihilation or radioactive decay. Gamma rays are generally characterized as electromagnetic radiation having the highest frequency and energy, and also the shortest wavelength (below about 10 picometer), within the electromagnetic spectrum. Gamma rays consist of high energy photons with energies above about 100 keV. Nuclear physics is the branch of physics concerned with the nucleus of the atom. ... Image File history File links CNO_Cycle. ... Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting radiation in the form of particles or electromagnetic waves. ... For the generation of electrical power by fission, see Nuclear power plant. ... The deuterium-tritium (D-T) fusion reaction is considered the most promising for producing fusion power. ... Alpha decay Alpha decay is a type of radioactive decay in which an atom emits an alpha particle (two protons and two neutrons bound together into a particle identical to a helium nucleus) and transforms (or decays) into an atom with a mass number 4 less and atomic number 2... In nuclear physics, beta decay (sometimes called neutron decay) is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted. ... Cluster decay is the nuclear process in which a radioactive atom emits a cluster of neutrons and protons. ... In the process of beta decay unstable nuclei decay by converting a neutron in the nucleus to a proton and emitting an electron and anti-neutrino. ... Double electron capture is a decay mode of atomic nucleus. ... . Internal conversion is a radioactive decay process where an excited nucleus interacts with an electron in one of the lower electron shells, causing the electron to be emitted from the atom. ... Internal conversion or isomeric transition is the act of returning from an excited state by an atom or molecule. ... Neutron emission is a type of radioactive decay in which an atom contains excess neutrons and a neutron is simply ejected from the nucleus. ... Positron emission is a type of beta decay, sometimes referred to as beta plus (β+). In beta plus decay, a proton is converted to a neutron via the weak nuclear force and a beta plus particle (a positron) and a neutrino are emitted. ... Proton emission (also known as proton radioactivity) is a type of radioactive decay in which a proton is ejected from a nucleus. ... Electron capture is a decay mode for isotopes that will occur when there are too many protons in the nucleus of an atom, and there isnt enough energy to emit a positron; however, it continues to be a viable decay mode for radioactive isotopes that can decay by positron... The process of neutron capture can proceed in two ways - as a rapid process (an r-process) or a slow process (an s-process). ... The R process (R for rapid) is a neutron capture process for radioactive elements which occurs in high neutron density, high temperature conditions. ... This article or section does not cite its references or sources. ... The p-process is a nucleosynthesis process occurring in core-collapse supernovae (see also supernova nucleosynthesis) responsible for the creation of some proton-rich atomic nuclei heavier than iron. ... The rp process (rapid proton capture process) consists of consecutive proton captures onto seed nuclei to produce heavier elements. ... Spontaneous fission (SF) is a form of radioactive decay characteristic of very heavy isotopes, and is theoretically possible for any atomic nucleus whose mass is greater than or equal to 100 amu (elements near ruthenium). ... In general, spallation is a process in which fragments of material are ejected from a body due to impact or stress. ... Cosmic ray spallation is a form of naturally occuring nuclear fission and nucleosynthesis. ... Photodisintegration is a physics process in which extremely high energy Gamma rays impact an atomic nucleus and cause it to break apart in a nuclear fission reaction. ... Nucleosynthesis is the process of creating new atomic nuclei from preexisting nucleons (protons and neutrons). ... Cross section of a red giant showing nucleosynthesis and elements formed Stellar nucleosynthesis is the collective term for the nuclear reactions taking place in stars to build the nuclei of the heavier elements. ... In cosmology, Big Bang nucleosynthesis (or primordial nucleosynthesis) refers to the production of nuclei other than H-1, the normal, light hydrogen, during the early phases of the universe, shortly after the Big Bang. ... Supernova nucleosynthesis refers to the production of new chemical elements inside supernovae. ... For the SI unit of radioactivity, see Becquerel. ... This article is about the chemist and physicist. ... Pierre Curie (May 15, 1859 – died April 19, 1906) was a French physicist, a pioneer in crystallography, magnetism, piezoelectricity and radioactivity. ... Hans Albrecht Bethe (pronounced bay-tuh; July 2, 1906 – March 6, 2005), was a German-American physicist who won the Nobel Prize in Physics in 1967 for his work on the theory of stellar nucleosynthesis. ... Gamma Ray is a power metal band from north of Germany, founded by former Helloween guitarist, singer, and songwriter Kai Hansen. ... Gamma (uppercase Γ, lowercase γ) is the third letter of the Greek alphabet. ... This box:      Electromagnetic (EM) radiation is a self-propagating wave in space with electric and magnetic components. ... In modern physics the photon is the elementary particle responsible for electromagnetic phenomena. ... Properties For other meanings of Atom, see Atom (disambiguation). ... Naturally occurring electron-positron annihilation as a result of beta plus decay Feynman Diagram of Electron-Positron Annihilation Electron-positron annihilation occurs when an electron and a positron (the electrons anti-particle) collide. ... Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting radiation in the form of particles or electromagnetic waves. ... This box:      Electromagnetic (EM) radiation is a self-propagating wave in space with electric and magnetic components. ... Picometre (American spelling: picometer) is an SI measure of length that is equal to 10−12 of a metre. ... Legend γ = Gamma rays HX = Hard X-rays SX = Soft X-Rays EUV = Extreme ultraviolet NUV = Near ultraviolet Visible light NIR = Near infrared MIR = Moderate infrared FIR = Far infrared Radio waves EHF = Extremely high frequency (Microwaves) SHF = Super high frequency (Microwaves) UHF = Ultra high frequency VHF = Very high frequency HF = High... In physics, the photon (from Greek φως, phōs, meaning light) is the quantum of the electromagnetic field; for instance, light. ... The electronvolt (symbol eV) is a unit of energy. ...


Hard X-rays overlap the range of "long"-wavelength (lower energy) gamma rays, however the distinction between the two terms depends on the source of the radiation, not its wavelength; X-ray photons are generated by energetic electron processes, gamma rays by transitions within atomic nuclei. An X-ray picture (radiograph), taken by Wilhelm Röntgen in 1896, of his wife, Anna Bertha Ludwigs[1] hand X-rays (or Röntgen rays) are a form of electromagnetic radiation with a wavelength in the range of 10 to 0. ...


Due to their high energy content, gamma rays can cause serious damage when absorbed by living cells.

Contents

Properties

Shielding

Artist's impression of an emission of a gamma ray (γ) from an atomic nucleus
Artist's impression of an emission of a gamma ray (γ) from an atomic nucleus

Shielding gamma rays requires large amounts of mass. They are better absorbed by materials with high atomic numbers and high density. The higher the energy of the gamma rays, the thicker the shielding required. Materials for shielding gamma rays are typically measured by the thickness required to reduce the intensity of the gamma rays by one half (the half value layer or HVL). For example, gamma rays that require 1 cm (0.4 inches) of lead to reduce their intensity by 50% will also have their intensity reduced in half by 6 cm (2½ inches) of concrete or 9 cm (3½ inches) of packed dirt. Image File history File links Gamma_Decay. ... Image File history File links Gamma_Decay. ... In chemistry and physics, the atomic number (Z) is the number of protons found in the nucleus of an atom. ... General Name, Symbol, Number lead, Pb, 82 Chemical series Post-transition metals or poor metals Group, Period, Block 14, 6, p Appearance bluish gray Standard atomic weight 207. ... This article is about the construction material. ...




Matter interaction

The total absorption coefficient of aluminium (atomic number 13) for gamma rays, plotted versus gamma energy, and the contributions by the three effects. Over most of the energy region shown, the Compton effect dominates.
The total absorption coefficient of aluminium (atomic number 13) for gamma rays, plotted versus gamma energy, and the contributions by the three effects. Over most of the energy region shown, the Compton effect dominates.
The total absorption coefficient of lead (atomic number 82) for gamma rays, plotted versus gamma energy, and the contributions by the three effects. Here, the photo effect dominates at low energy. Above 5 MeV, pair production starts to dominate
The total absorption coefficient of lead (atomic number 82) for gamma rays, plotted versus gamma energy, and the contributions by the three effects. Here, the photo effect dominates at low energy. Above 5 MeV, pair production starts to dominate

When a gamma ray passes through matter, the probability for absorption in a thin layer is proportional to the thickness of that layer. This leads to an exponential decrease of intensity with thickness. The exponential absorption holds only for a narrow beam of gamma rays. If a wide beam of gamma rays passes through a thick slab of concrete, the scattering from the sides reduces the absorption. Image File history File links Download high resolution version (1692x1188, 10 KB) Summary Licensing File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Gamma ray ... Image File history File links Download high resolution version (1692x1188, 10 KB) Summary Licensing File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Gamma ray ... Image File history File links Download high resolution version (1692x1188, 10 KB) Summary Licensing File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Gamma ray ... Image File history File links Download high resolution version (1692x1188, 10 KB) Summary Licensing File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Gamma ray ... A quantity is said to be subject to exponential decay if it decreases at a rate proportional to its value. ...

 I(d) = I_0 cdot e ^{-mu d}.

Here, μ = nσ is the absorption coefficient, measured in cm−1, n the number of atoms per cm3 in the material, σ the absorption cross section in cm2 and d the thickness of material in cm. In nuclear and particle physics, the concept of a cross section is used to express the likelihood of interaction between particles. ...


In passing through matter, gamma radiation ionizes via three main processes: the photoelectric effect, Compton scattering, and pair production. A diagram illustrating the emission of electrons from a metal plate, requiring energy gained from an incoming photon to be more than the work function of the material. ... In physics, Compton scattering or the Compton effect, is the decrease in energy (increase in wavelength) of an X-ray or gamma ray photon, when it interacts with matter. ... Pair production refers to the creation of an elementary particle and its antiparticle, usually from a photon (or another neutral boson). ...

  • Photoelectric Effect: This describes the case in which a gamma photon interacts with and transfers its energy to an atomic electron, ejecting that electron from the atom. The kinetic energy of the resulting photoelectron is equal to the energy of the incident gamma photon minus the binding energy of the electron. The photoelectric effect is the dominant energy transfer mechanism for x-ray and gamma ray photons with energies below 50 keV (thousand electron volts), but it is much less important at higher energies.
  • Compton Scattering: This is an interaction in which an incident gamma photon loses enough energy to an atomic electron to cause its ejection, with the remainder of the original photon's energy being emitted as a new, lower energy gamma photon with an emission direction different from that of the incident gamma photon. The probability of Compton scatter decreases with increasing photon energy. Compton scattering is thought to be the principal absorption mechanism for gamma rays in the intermediate energy range 100 keV to 10 MeV. Compton scattering is relatively independent of the atomic number of the absorbing material.
  • Pair Production: By interaction with the electric field of a nucleus, the energy of the incident photon is converted into the mass of an electron-positron pair. Energy in excess of the equivalent rest mass of the two particles (1.02 MeV) appears as the kinetic energy of the pair and the recoil nucleus. At the end of the positron's range, it combines with a free electron. The entire mass of these two particles is then converted into two gamma photons of 0.51 MeV energy each.

The secondary electrons (and/or positrons) produced in any of these three processes frequently have enough energy to produce much ionization themselves. The electronvolt (symbol eV) is a unit of energy. ... The electronvolt (symbol eV) is a unit of energy. ... See also: List of elements by atomic number In chemistry and physics, the atomic number (also known as the proton number) is the number of protons found in the nucleus of an atom. ... In physics, the space surrounding an electric charge or in the presence of a time-varying magnetic field has a property called an electric field. ... The first detection of the positron in 1932 by Carl D. Anderson The positron is the antiparticle or the antimatter counterpart of the electron. ... In passing through matter, charged particles ionize and thus loose energy in many steps, until their energy is (almost) zero. ... Ionization is the physical process of converting an atom or molecule into an ion by changing the difference between the number of protons and electrons. ...


Gamma production

Gamma rays are often produced alongside other forms of radiation such as alpha or beta. When a nucleus emits an α or β particle, the daughter nucleus is sometimes left in an excited state. It can then jump down to a lower level by emitting a gamma ray in much the same way that an atomic electron can jump to a lower level by emitting visible light or ultraviolet radiation. Alpha decay Alpha decay is a type of radioactive decay in which an atom emits an alpha particle (two protons and two neutrons bound together into a particle identical to a helium nucleus) and transforms (or decays) into an atom with a mass number 4 less and atomic number 2... In nuclear physics, beta decay (sometimes called neutron decay) is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted. ... In nuclear physics, a decay product, also known as a daughter product, is a nuclide resulting from the radioactive decay of a parent or precursor nuclide. ... For other uses, see Ultraviolet (disambiguation). ...

Decay scheme of 60Co
Decay scheme of 60Co

Gamma rays, x-rays, visible light, and radio waves are all forms of electromagnetic radiation. The only difference is the frequency and hence the energy of the photons. Gamma rays are the most energetic. An example of gamma ray production follows. Image File history File links Cobalt-60_Decay_Scheme. ... Image File history File links Cobalt-60_Decay_Scheme. ... For other uses, see Light (disambiguation). ... This box:      Electromagnetic (EM) radiation is a self-propagating wave in space with electric and magnetic components. ... For other uses, see Frequency (disambiguation). ... In modern physics the photon is the elementary particle responsible for electromagnetic phenomena. ...


First 60Co decays to excited 60Ni by beta decay: Cobalt 60 is a Front 242 side project featuring Front 242s Jean-Luc de Meyer and Dominique Lallement. ... After absorbing energy, an electron may jump from the ground state to a higher energy excited state. ... Nickel (Ni) Standard atomic mass: 58. ... Beta particles are high-energy electrons emitted by certain types of radioactive nuclei such as potassium-40. ...

 {}^{60}hbox{Co};to;^{60}hbox{Ni*};+;e^-;+;overline{nu}_e.

Then the 60Ni drops down to the ground state (see nuclear shell model) by emitting two gamma rays in succession: In nuclear physics, the nuclear shell model is a model of the atomic nucleus. ...

 {}^{60}hbox{Ni*};to;^{60}hbox{Ni};+;gamma.

Gamma rays of 1.17 MeV and 1.33 MeV are produced.


Another example is the alpha decay of 241Am to form 237Np; this alpha decay is accompanied by gamma emission. In some cases, the gamma emission spectrum for a nucleus (daughter nucleus) is quite simple, (eg 60Co/60Ni) while in other cases, such as with (241Am/237Np and 192Ir/192Pt), the gamma emission spectrum is complex, revealing that a series of nuclear energy levels can exist. The fact that an alpha spectrum can have a series of different peaks with different energies reinforces the idea that several nuclear energy levels are possible. General Name, Symbol, Number americium, Am, 95 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery white Atomic mass (243) g/mol Electron configuration [Rn] 5f7 7s2 Electrons per shell 2, 8, 18, 32, 25, 8, 2 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number neptunium, Np, 93 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery metallic Atomic mass (237) g/mol Electron configuration [Rn] 5f4 6d1 7s2 Electrons per shell 2, 8, 18, 32, 22, 9, 2 Physical properties Phase solid Density (near r. ... Gamma (uppercase Γ, lowercase γ) is the third letter of the Greek alphabet. ... Iridium-192 (symbol Ir192m) is an isotope of Iridium. ...

Image of entire sky in 100 MeV or greater gamma rays as seen by the EGRET instrument aboard the CGRO spacecraft. Bright spots within the galactic plane are pulsars while those above and below the plane are thought to be quasars.

Because a beta decay is accompanied by the emission of a neutrino which also carries energy away, the beta spectrum does not have sharp lines, but instead is a broad peak. Hence from beta decay alone it is not possible to probe the different energy levels found in the nucleus. All sky map in gamma rays >100Mev from the egret instrument aboard the CGRO gamma ray telescope File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... All sky map in gamma rays >100Mev from the egret instrument aboard the CGRO gamma ray telescope File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Illustration of CGRO The Compton Gamma Ray Observatory(CGRO) was the second of the NASA Great Observatories to be launched to space, following the Hubble Space Telescope. ... It has been suggested that Radio pulsar be merged into this article or section. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... For other uses, see Neutrino (disambiguation). ...


In optical spectroscopy, it is well known that an entity which emits light can also absorb light at the same wavelength (photon energy). For instance, a sodium flame can emit yellow light as well as absorb the yellow light from a sodium vapour lamp. In the case of gamma rays, this can be seen in Mössbauer spectroscopy. Here, a correction for the energy lost by the recoil of the nucleus is made and the exact conditions for gamma ray absorption through resonance can be attained. See also list of optical topics. ... For other uses, see Wavelength (disambiguation). ... For sodium in the diet, see Salt. ... Mössbauer spectroscopy is a spectroscopic technique based on the Mössbauer effect. ...


This is similar to the Franck Condon effects seen in optical spectroscopy. The Franck-Condon principle is a rule in quantum chemistry that allows one to predict the intensity of a vibronic transition. ...


Uses

Gamma-ray Image of a truck taken with a VACIS (Vehicle and Container Imaging System)
Gamma-ray Image of a truck taken with a VACIS (Vehicle and Container Imaging System)

Because the wavelength of gamma radiation is so short, a single incident photon can impart significant damage to a living cell. This property means that gamma radiation is often used to kill living organisms, in a process called irradiation. Applications of this include sterilising medical equipment (as an alternative to autoclaves or chemical means), removing decay-causing bacteria from many foodstuffs or preventing fruit and vegetables from sprouting to maintain freshness and flavour. Image File history File links Size of this preview: 800 × 226 pixelsFull resolution (1195 × 337 pixel, file size: 161 KB, MIME type: image/gif) File historyClick on a date/time to view the file as it appeared at that time. ... Image File history File links Size of this preview: 800 × 226 pixelsFull resolution (1195 × 337 pixel, file size: 161 KB, MIME type: image/gif) File historyClick on a date/time to view the file as it appeared at that time. ... For the music band, see Gamma Ray (band). ... Intermodal Cargo Containers Non-intrusive cargo scanning or more specifically scanning of Intermodal freight containers is a technological challenge which sees a lot of research activity in last decade. ... Irradiation is the process by which an item is exposed to radiation. ... Front loading autoclaves are common Stovetop autoclaves need to be monitored carefully and are the simplest of all autoclaves Multiple large autoclaves are used for processing substantial quantities of laboratory equipment prior to reuse, and infectious material prior to disposal. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ...


Due to their tissue penetrating property, gamma rays/X-rays have a wide variety of medical uses such as in CT Scans and radiation therapy (see X-ray). However, as a form of ionizing radiation they have the ability to effect molecular changes, giving them the potential to cause cancer when DNA is affected. The molecular changes can also be used to alter the properties of semi-precious stones, and is often used to change white topaz into blue topaz. negron305 Cat scan redirects here. ... Varian Clinac 2100C Linear Accelerator Radiation therapy (or radiotherapy) is the medical use of ionizing radiation as part of cancer treatment to control malignant cells (not to be confused with radiology, the use of radiation in medical imaging and diagnosis). ... In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz... Radiation hazard symbol. ... Cancer is a class of diseases or disorders characterized by uncontrolled division of cells and the ability of these to spread, either by direct growth into adjacent tissue through invasion, or by implantation into distant sites by metastasis (where cancer cells are transported through the bloodstream or lymphatic system). ... The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... A selection of gemstone pebbles made by tumbling rough rock with abrasive grit, in a rotating drum. ...


Despite their cancer-causing properties, gamma rays are also used to treat some types of cancer. In the procedure called gamma-knife surgery, multiple concentrated beams of gamma rays are directed on the growth in order to kill the cancerous cells. The beams are aimed from different angles to focus the radiation on the growth while minimizing damage to the surrounding tissues. Cancer is a class of diseases or disorders characterized by uncontrolled division of cells and the ability of these to spread, either by direct growth into adjacent tissue through invasion, or by implantation into distant sites by metastasis (where cancer cells are transported through the bloodstream or lymphatic system). ... In medicine, Leksell Gamma Knife is a neurosurgical device used to treat brain tumors. ...

The Moon as seen in gamma rays by the Compton Gamma Ray Observatory. Surprisingly, the Moon is actually brighter than the Sun at gamma ray wavelengths.
The Moon as seen in gamma rays by the Compton Gamma Ray Observatory. Surprisingly, the Moon is actually brighter than the Sun at gamma ray wavelengths.

Gamma rays are also used for diagnostic purposes in nuclear medicine. Several gamma-emitting radioisotopes are used, one of which is technetium-99m. When administered to a patient, a gamma camera can be used to form an image of the radioisotope's distribution by detecting the gamma radiation emitted. Such a technique can be employed to diagnose a wide range of conditions (e.g. spread of cancer to the bones). Image of the Moon as seen in Gamma rays by the EGRET instrument aboard the Compton Gamma Ray Observatory. ... Image of the Moon as seen in Gamma rays by the EGRET instrument aboard the Compton Gamma Ray Observatory. ... Illustration of CGRO The Compton Gamma Ray Observatory(CGRO) was the second of the NASA Great Observatories to be launched to space, following the Hubble Space Telescope. ... Shown above is the bone scintigraphy of a young woman. ... A radionuclide is an atom with an unstable nucleus. ... General Name, Symbol, Number technetium, Tc, 43 Chemical series transition metals Group, Period, Block 7, 5, d Appearance silvery gray metal Standard atomic weight [98](0) g·mol−1 Electron configuration [Kr] 4d5 5s2 Electrons per shell 2, 8, 18, 13, 2 Physical properties Phase solid Density (near r. ... Diagrammatic cross section of a gamma camera detector A gamma camera is an imaging device, most commonly used as a medical imaging device in nuclear medicine. ...


Gamma ray detectors are also starting to be used in Pakistan as part of the Container Security Initiative (CSI). These US$5 million machines are advertised to scan 30 containers per hour. The objective of this technique is to pre-screen merchant ship containers before they enter U.S. ports. The Container Security Initiative is the most topical AFF ever. ... USD redirects here. ...


Health effects

Gamma rays are the most dangerous form of radiation emitted by a nuclear explosion because of the difficulty in shielding them. This is because gamma rays have the shortest wavelength, and therefore the highest energy, of all waves in the electromagnetic spectrum. It has been suggested that Nuclear explosive be merged into this article or section. ...


Gamma-rays are not stopped by the skin. They can induce DNA alteration by interfering with the genetic material of the cell. DNA double-strand breaks are generally accepted to be the most biologically significant lesion by which ionizing radiation causes cancer and hereditary disease.[1].


A study done on Russian nuclear workers exposed to external whole-body gamma radiation at high cumulative doses shows the link between radiation exposure and death from leukemia, lung, liver, skeletal and other solid cancers.[2]. Alongside radiation, gamma-rays also produce thermal burn injuries and induce an immunosuppressive effect.[3][4] Leukemia or leukaemia(Greek leukos λευκός, “white”; aima αίμα, “blood”) (see spelling differences) is a cancer of the blood or bone marrow and is characterized by an abnormal proliferation (production by multiplication) of blood cells, usually white blood cells (leukocytes). ... Immunosuppression is the medical suppression of the immune system. ...


Body response

After gamma-irradiation, and the breaking of DNA double-strands, a cell can repair the damaged genetic material to the limit of its capability[citation needed]. However, a study of Rothkamm and Lobrich has shown that the repairing process works well after high-dose exposure but is much slower in the case of a low-dose exposure. [5] This could mean that a chronic low-dose exposure cannot be fought by the body[citation needed]. The probability of detecting small alterations or of a detectable defect occurring is most likely small enough that the cell would replicate before initiating a full repair[citation needed]. Some cells can not detect their own genetic defects[citation needed].


Risk assessment

The natural outdoor exposure in Great Britain is in the range 20-40 nSv/h.[6] Natural exposure to gamma rays is about 1 to 2 mSv a year, and the average total amount of radiation received in one year per inhabitant in the USA is 3.6 mSv.[7] The sievert (symbol: Sv) is the SI derived unit of dose equivalent. ...


By comparison, the radiation dose from chest radiography is a fraction of the annual naturally occurring background radiation dose,[8] and the dose from fluoroscopy of the stomach is, at most, 0.05 Sv on the skin of the back. A radiograph of a right elbow-joint Radiography is the use of certain types of electromagnetic radiation—usually ionizing—to view objects. ... A modern fluoroscope. ...


For acute full-body equivalent dose, 1 Sv causes slight blood changes, 2-5 Sv causes nausea, hair loss, hemorrhaging and will cause death in many cases. More than 3 Sv will lead to death in less than two months in more than 80 percent of cases, and much over 4 Sv usually causes death (see Sievert).[clarify][citation needed] This article or section is in need of attention from an expert on the subject. ... The sievert (symbol: Sv) is the SI derived unit of dose equivalent. ...


For low dose exposure, for example among nuclear workers, who receive an average radiation dose of 19 mSv, the risk of dying from cancer (excluding leukemia) increases by 2 percent. For a dose of 100 mSv, that risk increase is at 10 percent. By comparison, it was 32 percent for the Atom Bomb survivors.[9]. Leukemia or leukaemia(Greek leukos λευκός, “white”; aima αίμα, “blood”) (see spelling differences) is a cancer of the blood or bone marrow and is characterized by an abnormal proliferation (production by multiplication) of blood cells, usually white blood cells (leukocytes). ...


References

  1. Kelly, K. (2005). Radiation may have positive effects on health: study -- Low, chronic doses of gamma radiation had beneficial effects on meadow voles University of Toronto
  1. ^ Rothkamm K. – Evidence for a lack of DNA double-strand break repair in human cells exposed to very low x-ray doses – Proceedings of the National Academy of Science of the USA, 2003; 100 (9) : 5057-5062.
  2. ^ Shilnikova D.L. et al. – Cancer mortality risk among workers at the Mayak nuclear complex – Radiation Research, 2003; 159 (6): 787-798
  3. ^ Ran X.Z. et al. – Effects of combined radiation and thermal burn injury on the survival of skin allograft and immune function in – Chinese Medical Journal, 1998; 111 (7): 634-637
  4. ^ Randall K. et al. – The effect of whole-body gamma-irradiation on localized beta-irradiation-induced skin reactions in mice – International Journal of Radiation Biology, 1992; 62 (6): 729-733.
  5. ^ Rothkamm K. – Evidence for a lack of DNA double-strand break repair in human cells exposed to very low x-ray doses – Proceedings of the National Academy of Science of the USA, 2003; 100 (9) : 5057-5062.
  6. ^ Department for Environment, Food and Rural Affairs (Defra) UK – Keys facts about radioactivity – 2003, http://www.defra.gov.uk/environment/statistics/radioact/kf/rakf03.htm
  7. ^ United Nations Scientific Committee on the Effects of Atomic Radiation Annex E: Medical radiation exposures – Sources and Effects of Ionizing – 1993, p. 249, New York, UN
  8. ^ US National Council on Radiation Protection and Measurements – NCRP Report No. 93 – pp 53-55, 1987. Bethesda, Maryland, USA, NCRP
  9. ^ IARC – Cancer risk following low doses of ionising radiation - a 15 country study – http://www.iarc.fr/ENG/Units/RCAa1.html

See also

Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting radiation in the form of particles or electromagnetic waves. ... For the generation of electrical power by fission, see Nuclear power plant. ... The deuterium-tritium (D-T) fusion reaction is considered the most promising for producing fusion power. ... Gamma spectroscopy is a radiochemistry measurement method that determines the energy and count rate of gamma rays emitted by radioactive substances. ... Gamma-ray astronomy is the astronomical study of the cosmos with gamma rays. ... The image above shows the optical afterglow of gamma ray burst GRB-990123 taken on January 23, 1999. ... Varian Clinac 2100C Linear Accelerator Radiation therapy (or radiotherapy) is the medical use of ionizing radiation as part of cancer treatment to control malignant cells (not to be confused with radiology, the use of radiation in medical imaging and diagnosis). ... High Energy X-rays or HEX-rays are very hard X-rays, with 80 keV - 1000 keV typically one order of magnitude higher in energy than conventional X-rays. ... The Radura logo, used to show a food has been treated with radiation. ... An alpha particle is deflected by a magnetic field Alpha particles or alpha rays are a form of particle radiation which are highly ionizing and have low penetration. ... Beta particles are high-energy electrons emitted by certain types of radioactive nuclei such as potassium-40. ... Neutron radiation consists of free neutrons. ... It has been suggested that this article or section be merged with delta ray. ... Epsilon Radiation is tertiary radiation caused by secondary radiation. ... An X-ray picture (radiograph), taken by Wilhelm Röntgen in 1896, of his wife, Anna Bertha Ludwigs[1] hand X-rays (or Röntgen rays) are a form of electromagnetic radiation with a wavelength in the range of 10 to 0. ...

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Legend γ = Gamma rays HX = Hard X-rays SX = Soft X-Rays EUV = Extreme ultraviolet NUV = Near ultraviolet Visible light NIR = Near infrared MIR = Moderate infrared FIR = Far infrared Radio waves EHF = Extremely high frequency (Microwaves) SHF = Super high frequency (Microwaves) UHF = Ultra high frequency VHF = Very high frequency HF = High... In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz... For other uses, see Ultraviolet (disambiguation). ... Visible light redirects here. ... For other uses, see Infrared (disambiguation). ... Electromagnetic waves sent at terahertz frequencies, known as terahertz radiation, terahertz waves, terahertz light, T-rays, T-light, T-lux and THz, are in the region of the electromagnetic spectrum between 300 gigahertz (3x1011 Hz) and 3 terahertz (3x1012 Hz), corresponding to the wavelength range starting at submillimeter (<1 millimeter... This article is about the type of Electromagnetic radiation. ... Visible light redirects here. ... Violet (named after the flower violet) is used in two senses: first, referring to the color of light at the short-wavelength end of the visible spectrum, approximately 380–420 nanometres (this is a spectral color). ... This article is about the colour. ... For other uses, see Green (disambiguation). ... A yellow Tulip. ... The orange, the fruit from which the modern name of the orange colour comes. ... For other uses, see Red (disambiguation). ... This article is about the type of Electromagnetic radiation. ... The W band of the microwave part of the electromagnetic spectrum and ranges from 75 to 111 GHz. ... The V band (vee-band) of the electromagnetic spectrum ranges from 50 to 75 GHz. ... The Ka band (kurz-above band) is a portion of the K band of the microwave band of the electromagnetic spectrum. ... K band is a portion of the electromagnetic spectrum in the microwave range of frequencies ranging between 12 to 63 GHz. ... The Ku band (kay-yoo kurz-under band) is a portion of the electromagnetic spectrum in the microwave range of frequencies ranging from 11 to 18 GHz. ... The X band (3-cm radar spot-band) of the microwave band of the electromagnetic spectrum roughly ranges from 5. ... C band (compromise band) is a portion of electromagnetic spectrum in the microwave range of frequencies ranging from 4 to 6 GHz. ... The S band ranges from 2 to 4 GHz. ... L band (20-cm radar long-band) is a portion of the microwave band of the electromagnetic spectrum ranging roughly from 0. ... Radio frequency, or RF, refers to that portion of the electromagnetic spectrum in which electromagnetic waves can be generated by alternating current fed to an antenna. ... Extremely high frequency is the highest radio frequency band. ... Microwave Slang for small waves, like at a beach, often used by surfers. ... This article is about the radio frequency. ... Very high frequency (VHF) is the radio frequency range from 30 MHz (wavelength 10 m) to 300 MHz (wavelength 1 m). ... High frequency (HF) radio frequencies are between 3 and 30 MHz. ... Medium frequency (MF) refers to radio frequencies (RF) in the range of 300 kHz to 3000 kHz. ... Low Frequency or LF refers to Radio Frequencies (RF) in the range of 30–300 kHz. ... Very low frequency or VLF refers to radio frequencies (RF) in the range of 3 to 30 kHz. ... Ultra Low Frequency (ULF) is the frequency range between 300 hertz and 3000 hertz. ... Super Low Frequency (SLF) is the frequency range between 30 hertz and 300 hertz. ... Extremely low frequency (ELF) is the band of radio frequencies from 3 to 30 Hz. ... For other uses, see Wavelength (disambiguation). ... This article is about the type of Electromagnetic radiation. ... A solid-state, analog shortwave receiver Shortwave radio operates between the frequencies of 3 MHz (3,000 kHz) and 30 MHz (30,000 kHz) [1] and came to be referred to as such in the early days of radio because the wavelengths associated with this frequency range were shorter than... Mediumwave radio transmissions serves as the most common band for broadcasting. ... This article does not cite any references or sources. ... Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting radiation in the form of particles or electromagnetic waves. ... Alpha decay Alpha decay is a type of radioactive decay in which an atom emits an alpha particle (two protons and two neutrons bound together into a particle identical to a helium nucleus) and transforms (or decays) into an atom with a mass number 4 less and atomic number 2... In nuclear physics, beta decay (sometimes called neutron decay) is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted. ... Cluster decay is the nuclear process in which a radioactive atom emits a cluster of neutrons and protons. ... In the process of beta decay unstable nuclei decay by converting a neutron in the nucleus to a proton and emitting an electron and anti-neutrino. ... Double electron capture is a decay mode of atomic nucleus. ... . Internal conversion is a radioactive decay process where an excited nucleus interacts with an electron in one of the lower electron shells, causing the electron to be emitted from the atom. ... Internal conversion or isomeric transition is the act of returning from an excited state by an atom or molecule. ... Spontaneous fission (SF) is a form of radioactive decay characteristic of very heavy isotopes, and is theoretically possible for any atomic nucleus whose mass is greater than or equal to 100 amu (elements near ruthenium). ... Neutron emission is a type of radioactive decay in which an atom contains excess neutrons and a neutron is simply ejected from the nucleus. ... Positron emission is a type of beta decay, sometimes referred to as beta plus (β+). In beta plus decay, a proton is converted to a neutron via the weak nuclear force and a beta plus particle (a positron) and a neutrino are emitted. ... Proton emission (also known as proton radioactivity) is a type of radioactive decay in which a proton is ejected from a nucleus. ... Electron capture is a decay mode for isotopes that will occur when there are too many protons in the nucleus of an atom, and there isnt enough energy to emit a positron; however, it continues to be a viable decay mode for radioactive isotopes that can decay by positron... The process of neutron capture can proceed in two ways - as a rapid process (an r-process) or a slow process (an s-process). ... Cross section of a red giant showing nucleosynthesis and elements formed Stellar nucleosynthesis is the collective term for the nuclear reactions taking place in stars to build the nuclei of the heavier elements. ... Overveiw of the proton-proton chain. ... This article does not cite its references or sources. ... The alpha reactions is one of two class of fusion reactions by which stars convert helium into heavier elements, the other being the triple_alpha process. ... Overview of the Triple-alpha process. ... The carbon burning process is a nuclear fusion reaction that occurs in massive stars (at least 4 MSun at birth) that have used up the lighter elements in their cores. ... Neon burning process is a set of nuclear fusion reactions that take place in massive stars (at least 8 MSun). ... The oxygen burning process is a nuclear fusion reaction that occurs in massive stars that have used up the lighter elements in their cores. ... In astrophysics, silicon burning is a nuclear fusion reaction which occurs in massive stars. ... The R process (R for rapid) is a neutron capture process for radioactive elements which occurs in high neutron density, high temperature conditions. ... This article or section does not cite its references or sources. ... The p-process is a nucleosynthesis process occurring in core-collapse supernovae (see also supernova nucleosynthesis) responsible for the creation of some proton-rich atomic nuclei heavier than iron. ... The rp process (rapid proton capture process) consists of consecutive proton captures onto seed nuclei to produce heavier elements. ...

  Results from FactBites:
 
Gamma ray - Wikipedia, the free encyclopedia (1887 words)
Gamma rays (often denoted by the Greek letter gamma, γ) are an energetic form of electromagnetic radiation produced by radioactive decay or other nuclear or subatomic processes such as electron-positron annihilation.
Gamma rays are a form of ionizing radiation; they are more penetrating than either alpha or beta radiation (neither of which is electromagnetic radiation), but less ionizing.
Gamma rays, x-rays, visible light, and UV rays are all forms of electromagnetic radiation.
Gamma ray burst - Wikipedia, the free encyclopedia (3642 words)
Optical afterglow of gamma ray burst GRB-990123 (the bright dot within the white square and in the enlarged cutout) on 23 January 1999.
The damage from a gamma ray burst would probably be significantly greater than a supernova at the same distance.
A Soft gamma repeater is a type of magnetar which emits large bursts of gamma rays and X-rays at irregular intervals.
  More results at FactBites »

 
 

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