query: what is the reason for irradiating food with gamma rays

pos: Food irradiation Food irradiation Food irradiation is the process of exposing food and food packaging to ionizing radiation. Ionizing radiation, such as from gamma rays, x-rays, or electron beams, is energy that can be transmitted without direct contact to the source of the energy (radiation) capable of freeing electrons from their atomic bonds (ionization) in the targeted food. The radiation can be emitted by a radioactive substance or generated electrically. This treatment is used to improve food safety by extending product shelf-life (preservation), reducing the risk of foodborne illness, delaying or eliminating sprouting or ripening, by sterilization of foods, and as a

neg: Philippine Nuclear Research Institute Electron Beams, it is used for the sterilization of food and medical devices as well as for refining electrical components such as wires and semiconductors. Electron Beams emit radiation faster than gamma rays. An average gamma ray would take hours to irradiate an object while an electron beam may take only seconds. The next is the Gammacell-220, that is used for irradiating small samples of objects and in regulating dosimeters. The last facility is the Multipurpose Irradiation Facility. It is multi-purpose gamma ray irradiator which may be used for various applications such as elimination of harmful bacteria, improvement of agriculture

neg: Gamma ray sample of gamma ray-emitting material that is used for irradiating or imaging is known as a gamma source. It is also called a radioactive source, isotope source, or radiation source, though these more general terms also apply to alpha- and beta-emitting devices. Gamma sources are usually sealed to prevent radioactive contamination, and transported in heavy shielding. Gamma rays are produced during gamma decay, which normally occurs after other forms of decay occur, such as alpha or beta decay. An excited nucleus can decay by the emission of an or particle. The daughter nucleus that results is usually left in an

neg: Beryl is subjected to heat treatment, though the color returns with irradiation. The pale blue color of aquamarine is attributed to Fe. Fe ions produce golden-yellow color, and when both Fe and Fe are present, the color is a darker blue as in maxixe. Decoloration of maxixe by light or heat thus may be due to the charge transfer between Fe and Fe. Dark-blue maxixe color can be produced in green, pink or yellow beryl by irradiating it with high-energy particles (gamma rays, neutrons or even X-rays). In the United States, aquamarines can be found at the summit of Mt. Antero

neg: Difluorophosphate earths, difluorophosphates decompose firstly by giving off POF forming a monofluorophosphate (POF) compound, and then this in turn decomposes to an orthophosphate compound. Difluorophosphate salts are normally soluble and stable in water. However, in acidic or alkaline conditions they can be hydrolyzed to monofluorophosphates and hydrofluoric acid. The caesium and potassium salts are the least soluble. Irradiating potassium difluorophosphate with gamma rays can make the free radicals POF, POF and . Difluorphosphoric acid (HPOF) is one of the fluorophosphoric acids. It is produced when phosphoryl fluoride reacts with water. POF + HO → HPOF + HF. This in turn is

neg: Gamma ray rays provide information about some of the most energetic phenomena in the universe; however, they are largely absorbed by the Earth's atmosphere. Instruments aboard high-altitude balloons and satellites missions, such as the Fermi Gamma-ray Space Telescope, provide our only view of the universe in gamma rays. Gamma-induced 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. Non-contact industrial sensors commonly use sources of gamma radiation in refining, mining, chemicals, food, soaps and detergents, and pulp and paper industries, for the measurement of levels, density, and

neg: Radiation therapy 50 grams, valued at £800,000, or $50 million in 2005 dollars. The invention of the nuclear reactor in the Manhattan Project during World War 2 made possible the production of artificial radioisotopes for radiotherapy. Cobalt therapy, teletherapy machines using megavolt gamma rays emitted by cobalt-60, a radioisotope produced by irradiating ordinary cobalt metal in a reactor, revolutionized the field between the 1950s and the early 1980s. Cobalt machines were relatively cheap, robust and simple to use, although due to its 5.27 year half-life the cobalt had to be replaced about every 5 years. Medical linear particle accelerators, developed since the

neg: Godiva device Godiva device The Lady Godiva device was an unshielded, pulsed nuclear reactor originally situated at the Los Alamos National Laboratory (LANL), near Santa Fe, New Mexico. It was one of a number of criticality devices within Technical Area 18 (TA-18). Specifically, it was used to produce bursts of neutrons and gamma rays for irradiating test samples, and inspired development of Godiva-like reactors. The radiation source within the Godiva device was a fissile metallic mass (usually highly enriched U), about in diameter. This was located at the top of a high metal tower. The burst of radiation was produced when a

neg: X-ray astronomy detector 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,

neg: Induced gamma emission written In(γ,γ)In. The product nuclide carries an "m" to denote that it has a long enough half life (4.5 h in this case) to qualify as being a nuclear isomer. That is what made the experiment possible in 1939 because the researchers had hours to remove the products from the irradiating environment and then to study them in a more appropriate location. With projectile photons, momentum and energy can be conserved only if the incident photon, X-ray or gamma, has precisely the energy corresponding to the difference in energy between the initial state of the target nucleus and some excited

neg: Gamma-ray astronomy Gamma-ray astronomy Gamma-ray astronomy is the astronomical observation of gamma rays, the most energetic form of electromagnetic radiation, with photon energies above 100 keV. Radiation below 100 keV is classified as X-rays and is the subject of X-ray astronomy. In most known cases, gamma rays from solar flare and Earth's atmosphere)are generated in the MeV range, but it is now known that gamma rays in the GeV range can also be generated by solar flares. Formerly, it was believed that gamma rays in the GeV range do not originate in the Solar System. As GeV gamma rays are important in

neg: Astrophysical X-ray source 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

neg: Ultra-high-energy gamma ray Ultra-high-energy gamma ray Ultra-high-energy gamma rays are gamma rays with photon energies higher than 100 TeV (0.1 PeV). They have a frequency higher than 2.42 × 10 Hz and a wavelength shorter than 1.24 × 10 m. , they are theoretical only and have not been detected. The highest energy astronomical sourced gamma rays detected are very-high-energy gamma rays. Ultra-high-energy gamma rays are of importance because they may reveal the source of cosmic rays. Discounting the relatively weak effect of gravity, they travel in a straight line from their source to an observer. This is unlike cosmic rays which have

neg: Irradiation disposables such as syringes, and sterilize food. Ionizing radiation (electron beams, X-rays and gamma rays) may be used to kill bacteria in food or other organic material, including blood. Food irradiation, while effective, is seldom used due to problems with public acceptance. Irradiation is used in diagnostic imaging, cancer therapy and blood transfusion. In 2011 researchers found that irradiation was successful in the novel theranostic technique involving co-treatment with heptamethine dyes to elucidate tumor cells and attenuate their growth with minimal side effects. Ion irradiation is routinely used to implant impurities atoms into materials, especially semiconductors, to modify their properties.

neg: Food irradiation sites of these collisions chemical bonds are broken, creating short lived radicals (e.g. the hydroxyl radical, the hydrogen atom and solvated electrons). These radicals cause further chemical changes by bonding with and or stripping particles from nearby molecules. When collisions damage DNA or RNA, effective reproduction becomes unlikely, also when collisions occur in cells, cell division is often suppressed. Irradiation (within the accepted energy limits, as 10 MeV for electrons, 5 MeV for X-rays [US 7.5 MeV] and gamma rays from Cobalt-60) can not make food radioactive, but it does produce radiolytic products, and free radicals in the food. A

neg: Food irradiation and food for hospital patients. Gamma irradiation is produced from the radioisotopes cobalt-60 and caesium-137, which are derived by neutron bombardment of cobalt-59 and as a nuclear source by-product, respectively. Cobalt-60 is the most common source of gamma rays for food irradiation in commercial scale facilities as it is water insoluble and hence has little risk of environmental contamination by leakage into the water systems. As for transportation of the radiation source, cobalt-60 is transported in special trucks that prevent release of radiation and meet standards mentioned in the Regulations for Safe Transport of Radioactive Materials of the International Atomic

neg: Commonly used gamma-emitting isotopes a metastable state of barium-137 (). Barium-137m has a half-life of minutes and is responsible for all of the gamma ray emission. The ground state of barium-137 is stable. The gamma ray (photon) energy of Ba-137m is about 662 keV. These gamma rays can be used, for example, in radiotherapy such as for the treatment of cancer, in food irradation, or in industrial gauges or sensors. Cs-137 is not widely used for industrial radiography as other nuclides, such as cobalt-60 or iridium-192 for example, offer higher radiation output for a given volume. Iodine-131 is another important gamma-emitting radionuclide produced as

neg: Food irradiation a decrease of 14% in the total quantity of products irradiated in the EU compared to the previous year 2012 (7 972 tonnes). The U.S. Food and Drug Administration and the U.S. Department of Agriculture have approved irradiation of the following foods and purposes: Food irradiation Food irradiation is the process of exposing food and food packaging to ionizing radiation. Ionizing radiation, such as from gamma rays, x-rays, or electron beams, is energy that can be transmitted without direct contact to the source of the energy (radiation) capable of freeing electrons from their atomic bonds (ionization) in the targeted food.

neg: Cobalt therapy Project during the World War II made possible the creation of artificial radioisotopes for radiotherapy. Cobalt-60, produced by neutron irradiation of ordinary cobalt metal in a reactor, is a high activity gamma ray emitter, emitting 1.17 and 1.33 MeV gamma rays with an activity of 44 TBq/g (about 1100 Ci/g). The main reason for its wide use in radiotherapy is that it has a longer half-life, 5.27 years, than many other gamma emitters. However this half life still requires cobalt sources to be replaced about every 5 years. In 1949, Dr. Harold E. Johns of the University of Saskatchewan sent

neg: Gamma ray gamma ray spectra. Gamma spectroscopy is the study of the energetic transitions in atomic nuclei, which are generally associated with the absorption or emission of gamma rays. As in optical spectroscopy (see Franck–Condon effect) the absorption of gamma rays by a nucleus is especially likely (i.e., peaks in a "resonance") when the energy of the gamma ray is the same as that of an energy transition in the nucleus. In the case of gamma rays, such a resonance is seen in the technique of Mössbauer spectroscopy. In the Mössbauer effect the narrow resonance absorption for nuclear gamma absorption can be

neg: Gamma-ray spectrometer are released, which scatter and collide with other nuclei. The nuclei get "excited" in the process, and emit gamma rays to release the extra energy so they can return to their normal rest state. Some elements like potassium, uranium, and thorium are naturally radioactive and give off gamma rays as they decay, but all elements can be excited by collisions with cosmic rays to produce gamma rays. The HEND and Neutron Spectrometers on GRS directly detect scattered neutrons, and the gamma sensor detects the gamma rays. By measuring neutrons, it is possible to calculate the abundance of hydrogen, thus inferring

neg: Gamma ray radiometric units and quantities for radiation protection have been defined and developed from 1953 onwards. These are: The conventional distinction between X-rays and gamma rays has changed over time. Originally, the electromagnetic radiation emitted by X-ray tubes almost invariably had a longer wavelength than the radiation (gamma rays) emitted by radioactive nuclei. Older literature distinguished between X- and gamma radiation on the basis of wavelength, with radiation shorter than some arbitrary wavelength, such as 10 m, defined as gamma rays. Since the energy of photons is proportional to their frequency and inversely proportional to wavelength, this past distinction between X-rays

neg: Annihilation radiation Annihilation radiation Annihilation radiation is a term used in Gamma spectroscopy for the gamma radiation produced when a particle and its antiparticle collide and annihilate. Most commonly, this refers to 511-keV gamma rays produced by a normal (negative) electron colliding with a positron. Annihilation radiation is not monoenergetic, unlike gamma rays produced by radioactive decay. The production mechanism of annihilation radiation introduces Doppler broadening. The annihilation peak produced in a gamma spectrum by annihilation radiation therefore has a higher full width at half maximum (FWHM) than other gamma rays in spectrum. The difference is more apparent with high resolution detectors,

neg: Gamma-ray astronomy many orders of magnitude larger than a satellite. In April 2018, the largest catalog yet of high-energy Gamma Ray sources in space was published. Gamma-ray astronomy Gamma-ray astronomy is the astronomical observation of gamma rays, the most energetic form of electromagnetic radiation, with photon energies above 100 keV. Radiation below 100 keV is classified as X-rays and is the subject of X-ray astronomy. In most known cases, gamma rays from solar flare and Earth's atmosphere)are generated in the MeV range, but it is now known that gamma rays in the GeV range can also be generated by solar flares. Formerly,

neg: Compton scattering is of prime importance to radiobiology, as it is the most probable interaction of gamma rays and high energy X-rays with atoms in living beings and is applied in radiation therapy. In material physics, Compton scattering can be used to probe the wave function of the electrons in matter in the momentum representation. Compton scattering is an important effect in gamma spectroscopy which gives rise to the Compton edge, as it is possible for the gamma rays to scatter out of the detectors used. Compton suppression is used to detect stray scatter gamma rays to counteract this effect. Magnetic Compton

neg: Reuven Ramaty High Energy Solar Spectroscopic Imager to image solar flares in energetic photons from soft X-rays (~3 keV) to gamma rays (up to ~20 MeV) and to provide high resolution spectroscopy up to gamma-ray energies of ~20 MeV. Furthermore, it had the capability to perform spatially resolved spectroscopy with high spectral resolution. Researchers believe that much of the energy released during a flare is used to accelerate, to very high energies, electrons (emitting primarily X-rays) and protons and other ions (emitting primarily gamma rays). The new approach of the RHESSI mission was to combine, for the first time, high-resolution imaging in hard X-rays and gamma rays

neg: Electromagnetic spectrum to 10 meters thickness of water. This is an amount sufficient to block almost all astronomical X-rays (and also astronomical gamma rays—see below). After hard X-rays come gamma rays, which were discovered by Paul Ulrich Villard in 1900. These are the most energetic photons, having no defined lower limit to their wavelength. In astronomy they are valuable for studying high-energy objects or regions, however as with X-rays this can only be done with telescopes outside the Earth's atmosphere. Gamma rays are used experimentally by physicists for their penetrating ability and are produced by a number of radioisotopes. They are used

neg: Pulsational pair-instability supernova supported against gravitational pull from the core. If the energy density of gamma rays is suddenly reduced, then the outer layers of the star will collapse inwards. The sudden heating and compression of the core generates gamma rays energetic enough to be converted into an avalanche of electron-positron pairs, further reducing the pressure. When the collapse stops, the positrons find electrons and the pressure from gamma rays is driven up, again. Sufficiently energetic gamma rays can interact with nuclei, electrons, or one another to produce electron-positron pairs, and electron-positron pairs can annihilate, producing gamma rays. From Einstein's equation "E" =

neg: Targeted intra-operative radiotherapy relative biological effectiveness (RBE) of low-energy X-rays on tumour cells is higher when compared to high-energy X-rays or gamma rays which are delivered by linear accelerators. The radiation which is produced by mobile radiation systems has a limited range. For this reason, conventional walls are regarded sufficient to stop the radiation scatter produced in the operating room and no extra measures for radiation protection are necessary. This makes IORT for breast cancer by the TARGIT technique available in most operating rooms. The surgical technique is relatively simple but needs to be meticulously followed. In 1998, the International Society of IORT

neg: Energetic Gamma Ray Experiment Telescope pulsars. EGRET’s results also pointed out to scientists that the Earth’s Moon is particularly brighter than the Sun the majority of the time. EGRET provided scientists with information that allowed them into a new understanding of the universe. Energetic Gamma Ray Experiment Telescope The Energetic Gamma Ray Experiment Telescope (EGRET) was one of four instruments outfitted on NASA’s Compton Gamma Ray Observatory satellite. Since lower energy gamma rays cannot be accurately detected on Earth’s surface, EGRET was built to detect gamma rays while in space. EGRET was created for the purpose of detecting and collecting data on gamma rays ranging

neg: Gamma ray disciplines. In astrophysics gamma rays are conventionally defined as having photon energies above 100 keV and are the subject of gamma ray astronomy, while radiation below 100 keV is classified as X-rays and is the subject of X-ray astronomy. This convention stems from the early man-made X-rays, which had energies only up to 100 KeV, whereas many gamma rays could go to higher energies. A large fraction of astronomical gamma rays are screened by Earth's atmosphere. Gamma rays are ionizing radiation and are thus biologically hazardous. Due to their high penetration power, they can damage bone marrow and internal organs.

neg: Very-high-energy gamma ray source of cosmic rays. They travel in a straight line (in space-time) from their source to an observer. This is unlike cosmic rays which have their direction of travel scrambled by magnetic fields. Sources that produce cosmic rays will almost certainly produce gamma rays as well, as the cosmic ray particles interact with nuclei or electrons to produce photons or neutral pions which in turn decay to ultra-high-energy photons. The ratio of primary cosmic ray hadrons to gamma rays also gives a clue as to the origin of cosmic rays. Although gamma rays could be produced near the source of

neg: Gamma ray sources. The higher the energy of the gamma rays, the thicker the shielding made from the same shielding material is 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 (0.4″) of lead to reduce their intensity by 50% will also have their intensity reduced in half by of granite rock, 6 cm (2½″) of concrete, or 9 cm (3½″) of packed soil. However, the mass of this much concrete or soil is only

neg: Gamma ray or near thunderclouds. The most effusive solar flares emit across the entire EM spectrum, including γ-rays. The first confident observation occurred in 1972. Extraterrestrial, high energy gamma rays include the gamma ray background produced when cosmic rays (either high speed electrons or protons) collide with ordinary matter, producing pair-production gamma rays at 511 keV. Alternatively, bremsstrahlung are produced at energies of tens of MeV or more when cosmic ray electrons interact with nuclei of sufficiently high atomic number (see gamma ray image of the Moon at the beginning of this article, for illustration). The gamma ray sky (see illustration at

neg: Isotopes of oxygen Oxygen-15 is synthesized through deuteron bombardment of nitrogen-14 using a cyclotron. Oxygen-15 and nitrogen-13 are produced in the atmosphere when gamma rays (for example from lightning) knock neutrons out of oxygen-16 and nitrogen-14: The oxygen-15 isotope decays with a half-life of about two minutes to nitrogen-15, emitting a positron. The positron quickly annihilates with an electron, producing two gamma rays of about 511 keV. After a lightning bolt, this gamma radiation dies down with a half-life of two minutes, but these low-energy gamma rays go on average only about 90 metres through the air. Together with rays produced from positrons

neg: Gamma ray not from radioactive decay or particle annihilation, but rather in non-radioactive processes similar to X-rays. Although the gamma rays of astronomy often come from non-radioactive events, a few gamma rays in astronomy are specifically known to originate from gamma decay of nuclei (as demonstrated by their spectra and emission half life). A classic example is that of supernova SN 1987A, which emits an "afterglow" of gamma-ray photons from the decay of newly made radioactive nickel-56 and cobalt-56. Most gamma rays in astronomy, however, arise by other mechanisms. Gamma ray A gamma ray or gamma radiation (symbol γ or formula_1), is

neg: Pound–Rebka experiment The distance between this source and absorber was 22.5 meters (73.8 ft). The gamma rays traveled through a Mylar bag filled with helium to minimize scattering of the gamma rays. A scintillation counter was placed below the receiving Fe sample to detect the gamma rays that were not absorbed by the receiving sample. By vibrating the speaker cone the gamma ray source moved with varying speed, thus creating varying Doppler shifts. When the Doppler shift canceled out the gravitational blueshift, the receiving sample absorbed gamma rays and the number of gamma rays detected by the scintillation counter dropped accordingly. The

neg: Gamma ray by beta rays, followed by gamma rays as the most penetrating. Rutherford also noted that gamma rays were not deflected (or at least, not deflected) by a magnetic field, another property making them unlike alpha and beta rays. Gamma rays were first thought to be particles with mass, like alpha and beta rays. Rutherford initially believed that they might be extremely fast beta particles, but their failure to be deflected by a magnetic field indicated that they had no charge. In 1914, gamma rays were observed to be reflected from crystal surfaces, proving that they were electromagnetic radiation. Rutherford and

neg: Gamma ray and gamma rays can also be thought of in terms of its energy, with gamma rays considered to be higher energy electromagnetic radiation than are X-rays. However, since current artificial sources are now able to duplicate any electromagnetic radiation that originates in the nucleus, as well as far higher energies, the wavelengths characteristic of radioactive gamma ray sources vs. other types now completely overlap. Thus, gamma rays are now usually distinguished by their origin: X-rays are emitted by definition by electrons outside the nucleus, while gamma rays are emitted by the nucleus. Exceptions to this convention occur in astronomy, where

neg: Pair-instability supernova of black body radiation is directly proportional to the temperature. In very large hot stars with a temperature above about K, photons produced in the stellar core are primarily in the form of gamma rays, with a very high energy level. The pressure from these gamma rays helps to support the upper layers of the star against the inward pull of gravity. If the level of gamma rays (the energy density) is suddenly reduced, then the outer layers of the star will begin to collapse inwards. Sufficiently energetic gamma rays can interact with nuclei, electrons, or one another. They can

neg: Ultra-high-energy gamma ray their direction of travel scrambled by magnetic fields. Sources that produce cosmic rays will almost certainly produce gamma rays as well, as the cosmic ray particles interact with nuclei or electrons to produce photons or neutral pions which in turn decay to ultra-high-energy photons. The ratio of primary cosmic ray hadrons to gamma rays also gives a clue as to the origin of cosmic rays. Although gamma rays could be produced near the source of cosmic rays, they could also be produced by interaction with cosmic microwave background by way of the Greisen–Zatsepin–Kuzmin limit cutoff above 50 EeV. Ultra-high-energy gamma

neg: Gamma-ray astronomy with as much as 80 TeV. Observation of gamma rays first became possible in the 1960s. Their observation is much more problematic than that of X-rays or of visible light, because gamma-rays are comparatively rare, even a "bright" source needing an observation time of several minutes before it is even detected, and because gamma rays are difficult to focus, resulting in a very low resolution. The most recent generation of gamma-ray telescopes (2000s) have a resolution of the order of 6 arc minutes in the GeV range (seeing the Crab Nebula as a single "pixel"), compared to 0.5 arc seconds

neg: Cosmic-ray observatory about cosmic rays is using different detectors to observe aspects of a cosmic ray air shower. Methods of detection for gamma-rays: For example, while a visible light photon may have an energy of a few eV, a cosmic gamma ray may exceed a TeV (1,000,000,000,000 eV). Sometimes cosmic gamma rays (photons) are not grouped with nuclei cosmic rays. "In 1952, a simple and audacious experiment allowed the first observation of Cherenkov light produced by cosmic rays passing through the atmosphere, giving birth to a new field of astronomy". This work, involving minimal instrument expense (laughably a dustbin, a war-surplus parabolic

neg: Gamma ray energy of photons produced by nuclear reactions, and thus ultraviolet or lower energy photons produced by these processes would also be defined as "gamma rays". The only naming-convention that is still universally respected is the rule that electromagnetic radiation that is known to be of atomic nuclear origin is "always" referred to as "gamma rays", and never as X-rays. However, in physics and astronomy, the converse convention (that all gamma rays are considered to be of nuclear origin) is frequently violated. In astronomy, higher energy gamma and X-rays are defined by energy, since the processes that produce them may be

neg: Mössbauer effect state with accompanying emission of gamma rays, the emission generally causes the nucleus to recoil, and this takes energy from the emitted gamma rays. Thus the gamma rays do not have sufficient energy to excite a target nucleus to be examined. However, Mössbauer discovered that it is possible to have transitions in which the recoil is absorbed by a whole crystal in which the emitting nucleus is bound. Under these circumstances, the energy that goes into the recoil is a negligible portion of the energy of the transition. Therefore, the emitted gamma rays carry virtually all of the energy liberated

neg: Gamma ray his co-worker Edward Andrade measured the wavelengths of gamma rays from radium, and found that they were similar to X-rays, but with shorter wavelengths and (thus) higher frequency. This was eventually recognized as giving them more energy per photon, as soon as the latter term became generally accepted. A gamma decay was then understood to usually emit a gamma photon. Natural sources of gamma rays on Earth include gamma decay from naturally occurring radioisotopes such as potassium-40, and also as a secondary radiation from various atmospheric interactions with cosmic ray particles. Some rare terrestrial natural sources that produce gamma rays

neg: Therapeutic index reason), and polymyxin B. Radiotherapy aims to minimize the size of tumors and kill cancer cells with high energy. The source of high energy arises from x-rays, gamma rays, charged particles and heavy particles. The therapeutic ratio in radiotherapy for cancer treatment is related to the maximum radiation dose by which death of cancer cells is locally controlled and the minimum radiation dose by which cells in normal tissues have low acute and late morbidity. Both of parameters have sigmoidal dose-response curves. Thus, a favorable outcome in dose-response curve is the response of tumor tissue is greater than that of

neg: Gamma ray of to form ; which is followed by gamma emission. In some cases, the gamma emission spectrum of the daughter nucleus is quite simple, (e.g. /) while in other cases, such as with (/ and /), the gamma emission spectrum is complex, revealing that a series of nuclear energy levels exist. Gamma rays are produced in many processes of particle physics. Typically, gamma rays are the products of neutral systems which decay through electromagnetic interactions (rather than a weak or strong interaction). For example, in an electron–positron annihilation, the usual products are two gamma ray photons. If the annihilating electron

neg: Little Lost Robot harmless infrared rays rather than gamma rays. All of the other robots could not identify what type of radiation was being used because it wasn't part of their design, whereas the modified NS-2 had been through training at Hyper Base and had learned how to detect the difference in radiation types. The robot, finding himself discovered, then explains that the only way to prove itself better than a human is by never being found, and it tries to attack Dr. Calvin so that she cannot reveal she found the robot. Black and Bogert apply gamma rays on the robot, destroying

neg: X-ray 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

neg: Gamma-ray spectrometer doped lanthanum bromide. Spectrometers for space missions conversely tend to be of the germanium kind. When exposed to cosmic rays (charged particles from space thought to possibly originate in supernova and active galactic nuclei), chemical elements in soils and rocks emit uniquely identifiable signatures of energy in the form of gamma rays. The gamma-ray spectrometer looks at these signatures, or energies, coming from the elements present in the target soil. By measuring gamma rays coming from the target body, it is possible to calculate the abundance of various elements and how they are distributed around the planet's surface. Gamma rays,

neg: Gamma ray terrestrial gamma-ray flashes, that produce gamma rays from electron action upon the nucleus. Notable artificial sources of gamma rays include fission, such as occurs in nuclear reactors, as well as high energy physics experiments, such as neutral pion decay and nuclear fusion. Gamma rays and X-rays are both electromagnetic radiation and they overlap in the electromagnetic spectrum; so that over a range of energies they cannot be differentiated by detection only. One way to distinguish them is by their origin, and in the case of X-rays, the origin is outside the nucleus due to electron interaction. Terminology varies between scientific

neg: Energetic Gamma Ray Experiment Telescope production as a gamma ray entered the telescope. The calorimeter on the telescope was then used to record the data from the electron or positron. To reject other energy rays that would skew the data, scientists covered the telescope with a plastic scintillator anti-coincidence dome. The dome acted as a shield for the telescope and blocked out any unwanted energy rays. The telescope was calibrated to only record gamma rays entering the telescope at certain angles. As these gamma rays entered the telescope, the rays went through the telescopes spark chamber and started the production of an electron and positron.

neg: Gamma ray are annihilated by electrons, producing pairs of gamma rays that highlight cancer as the cancer often has a higher metabolic rate than the surrounding tissues. The most common gamma emitter used in medical applications is the nuclear isomer technetium-99m which emits gamma rays in the same energy range as diagnostic X-rays. When this radionuclide tracer is 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 (see also SPECT). Depending on which molecule has been labeled with the tracer, such techniques can be employed to diagnose

neg: Wu experiment gamma rays (γ). Hence the overall nuclear equation of the reaction is: Gamma rays are photons, and their release from the nickel-60 nuclei is an electromagnetic (EM) process. This is important because EM was known to respect P-conservation. Hence, the distribution of the emitted gamma rays acted as a control for the polarization of the emitted electrons "via" the weak interaction, as well as an indicator of the uniformity of the cobalt-60 atoms. Wu's experiment compared the distribution of gamma and electron emissions with the nuclear spins in opposite orientations. If the electrons were always found to be emitted in

neg: Energetic Gamma Ray Experiment Telescope Energetic Gamma Ray Experiment Telescope The Energetic Gamma Ray Experiment Telescope (EGRET) was one of four instruments outfitted on NASA’s Compton Gamma Ray Observatory satellite. Since lower energy gamma rays cannot be accurately detected on Earth’s surface, EGRET was built to detect gamma rays while in space. EGRET was created for the purpose of detecting and collecting data on gamma rays ranging in energy level from 30 MeV to 30 GeV. To accomplish its task, EGRET was equipped with a spark chamber, calorimeter, and plastic scintillator anti-coincidence dome. The spark chamber was used to induce a process called electron-positron pair

neg: Gamma ray Gamma rays from radioactive decay are in the energy range from a few keV to ~8 MeV, corresponding to the typical energy levels in nuclei with reasonably long lifetimes. The energy spectrum of gamma rays can be used to identify the decaying radionuclides using gamma spectroscopy. Very-high-energy gamma rays in the 100–1000 TeV range have been observed from sources such as the Cygnus X-3 microquasar. Natural sources of gamma rays originating on Earth are mostly as a result of radioactive decay and secondary radiation from atmospheric interactions with cosmic ray particles. However there are other rare natural sources, such as

neg: X-ray astronomy detector 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

neg: Physical factors affecting microbial life Physical factors affecting microbial life Microbes can be damaged or killed by elements of their physical environment such as temperature, radiation, or exposure to chemicals; these effects can be exploited in efforts to control pathogens, often for the purpose of food safety. Irradiation is the use of ionising gamma rays emitted by cobalt-60 and caesium-137, or, high-energy electrons and X-rays to inactivate microbial pathogens, particularly in the food industry. Bacteria such as "Deinococcus radiodurans" are particularly resistant to radiation, but are not pathogenic. Active microbes, such as "Corynebacterium aquaticum", "Pseudomonas putida", "Comamonas acidovorans", "Gluconobacter cerinus", "Micrococcus diversus" and "Rhodococcus rhodochrous",

neg: Ultra-high-energy gamma ray path of the photon causes pair production, so that photons coming in parallel to the geomagnetic field lines can survive intact till they meet the atmosphere. These photons that come through the magnetic window can make a Landau–Pomeranchuk–Migdal shower. Ultra-high-energy gamma ray Ultra-high-energy gamma rays are gamma rays with photon energies higher than 100 TeV (0.1 PeV). They have a frequency higher than 2.42 × 10 Hz and a wavelength shorter than 1.24 × 10 m. , they are theoretical only and have not been detected. The highest energy astronomical sourced gamma rays detected are very-high-energy gamma rays. Ultra-high-energy gamma

neg: Gamma ray cancer-causing properties, gamma rays are also used to treat some types of cancer, since the rays also kill cancer cells. In the procedure called gamma-knife surgery, multiple concentrated beams of gamma rays are directed to the growth in order to kill the cancerous cells. The beams are aimed from different angles to concentrate the radiation on the growth while minimizing damage to surrounding tissues. Gamma rays are also used for diagnostic purposes in nuclear medicine in imaging techniques. A number of different gamma-emitting radioisotopes are used. For example, in a PET scan a radiolabeled sugar called fludeoxyglucose emits positrons that

neg: Gamma spectroscopy the typical energy levels in nuclei with reasonably long lifetimes. Such sources typically produce gamma-ray "line spectra" (i.e., many photons emitted at discrete energies), whereas much higher energies (upwards of 1 TeV) may occur in the continuum spectra observed in astrophysics and elementary particle physics. The boundary between gamma rays and X rays is somewhat blurred, as X rays typically refer to the high energy electronic emission of atoms, which may extend to over 100 keV, whereas the lowest energy emissions of nuclei are typically termed gamma rays, even though their energies may be below 20 keV. The equipment used

neg: Muon contributions involving hadrons are important at the current level of precision, whereas these effects are not important for the electron. The muon's anomalous magnetic dipole moment is also sensitive to contributions from new physics beyond the Standard Model, such as supersymmetry. For this reason, the muon's anomalous magnetic moment is normally used as a probe for new physics beyond the Standard Model rather than as a test of QED. Muon g−2, a new experiment at Fermilab using the E821 magnet will improve the precision of this measurement. Since muons are much more deeply penetrating than X-rays or gamma rays, muon

neg: Nuclear resonance fluorescence Nuclear resonance fluorescence Nuclear resonance fluorescence (NRF) is a nuclear process in which a nucleus absorbs and emits high-energy photons called gamma rays. NRF interactions typically take place above 1 MeV, and most NRF experiments target heavy nuclei such as uranium and thorium This process is used for scanning cargo for contraband. Its far more effective than just using x-rays because x-rays can only see the shape of the item in question. With nuclear resonance fluorescence its possible to see what the molecular structure is and thus, distinguish between salt and cocaine without even opening the container. (from National Geographic

neg: Wireline (cabling) Modern density tools utilize a Cs-137 radioactive source to generate gamma rays which interact with the rock strata. Since higher density materials absorb gamma rays much better than lower density materials, a gamma ray detector in the wire line tool is able to accurately determine formation density by measuring the number and associated energy level of returning gamma rays that have interacted with the rock matrix. Density tools usually incorporate an extendable caliper arm, which is used both to press the radioactive source and detectors against the side of the bore and also to measure the exact width of the

neg: Neutron stimulated emission computed tomography nucleus in its ground state is struck by a fast neutron with kinetic energy greater than that of its first excited state, it can undergo an isomeric transition to one of its excited states by receiving the necessary energy from the fast neutron through inelastic scatter. Promptly (on the order of picoseconds, on average) after excitation, the excited nuclear isomer de-excites (either directly or through a series of cascades) to the ground state, emitting a characteristic gamma ray for each decay transition with energy equal to the difference in the energy levels involved (see induced gamma emission). After irradiating the

neg: Tunka experiment Tunka experiment The Tunka experiment now named TAIGA (Tunka Advanced Instrument for cosmic ray physics and Gamma Astronomy) measures air showers, which are initiated by charged cosmic rays or high energy gamma rays. TAIGA is situated in Siberia in the Tunka valley close to lake Baikal. Meanwhile, TAIGA consists of five different detector systems: Tunka-133, Tunka-Rex, and Tunka-Grande for charged cosmic rays; Tunka-HiSCORE and Tunka-IACT for gamma astronomy. From the measurements of each detector it is possible to reconstruct the arrival direction, energy and type of the cosmic rays, where the accuracy is enhanced by the combination of different detector

neg: Gamma ray logging 238U and 235U). These radioactive isotopes each emit gamma rays that have a characteristic energy level measured in MeV. The quantity and energy of these gamma rays can be measured by a scintillometer. A log of the spectroscopic response to natural gamma ray radiation is usually presented as a total gamma ray log that plots the weight fraction of potassium (%), thorium (ppm) and uranium (ppm). The primary standards for the weight fractions are geological formations with known quantities of the three isotopes. Natural gamma ray spectroscopy logs became routinely used in the early 1970s, although they had been studied

neg: Annihilation radiation such as Germanium detectors, than with low resolution detectors such as Sodium iodide detectors. Because of their well-defined energy (511 keV) and characteristic, Doppler-broadened shape, annihilation radiation can often be useful in defining the energy calibration of a gamma ray spectrum. Annihilation radiation Annihilation radiation is a term used in Gamma spectroscopy for the gamma radiation produced when a particle and its antiparticle collide and annihilate. Most commonly, this refers to 511-keV gamma rays produced by a normal (negative) electron colliding with a positron. Annihilation radiation is not monoenergetic, unlike gamma rays produced by radioactive decay. The production mechanism of

neg: Gamma ray right) is dominated by the more common and longer-term production of gamma rays that emanate from pulsars within the Milky Way. Sources from the rest of the sky are mostly quasars. Pulsars are thought to be neutron stars with magnetic fields that produce focused beams of radiation, and are far less energetic, more common, and much nearer sources (typically seen only in our own galaxy) than are quasars or the rarer gamma-ray burst sources of gamma rays. Pulsars have relatively long-lived magnetic fields that produce focused beams of relativistic speed charged particles, which emit gamma rays (bremsstrahlung) when those strike

neg: Telescope Gamma-ray Space Telescope]]. The detection of very high energy gamma rays, with shorter wavelength and higher frequency than regular gamma rays, requires further specialization. An example of this type of observatory is [[VERITAS]]. Very high energy gamma-rays are still photons, like visible light, whereas [[cosmic ray]]s includes particles like electrons, protons, and heavier nuclei. A discovery in 2012 may allow focusing gamma-ray telescopes. At photon energies greater than 700 keV, the index of refraction starts to increase again. [[High-energy astronomy]] requires specialized telescopes to make observations since most of these particles go through most metals and glasses. In other types

neg: Markarian 501 long with rise times of 1 minute have been measured by MAGIC. In these flares the higher energy gamma rays (of 1.2 Tev) were delayed 4 minutes over the 0.25 TeV gamma rays. This delay has led to various theories, including that space is bigger at small dimensions with a foamy quantum texture. The foam would create a variation in the speed of light for higher-energy light gamma-rays and the lower-energy radio waves and visible light. Such a variation would contradict Lorentz invariance, but could provide a clue for unification theory. However, observations of Dr. Floyd Stecker of NASA's Goddard

neg: Neutron detection as CdTe, and HgI have been successfully used as neutron detectors. These detectors rely upon the prompt gamma-ray emissions from the Cd(n, γ)Cd reaction (producing 558.6 keV and 651.3 keV gamma rays) and the Hg(n, γ) Hg reaction (producing 368.1 keV and 661.1 keV gamma rays). However, these semiconductor materials are designed for use as gamma-ray spectrometers and, hence, are intrinsically sensitive to the gamma-ray background. With adequate energy resolution, pulse height discrimination can be used to separate the prompt gamma-ray emissions from neutron interactions. However, the effective neutron detection efficiency is compromised because of the relatively small Compton ratio.

neg: X-ray fluorescence 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

neg: Pulsational pair-instability supernova then undergoes a core-collapse supernova or hypernova. It is possible that this is what occurred during the 1843 eruption of the primary star of the Eta Carinae star system although there is no substantial evidence supporting this. Gamma rays by stars of fewer than are not energetic enough to produce electron-positron pairs. Some of these stars will undergo supernovae at the end of their lives, but the causative mechanisms are unrelated to pair-instability. In stars of , a pulsational pair-instability supernova can occur. Stars like this are massive enough that the gamma rays are energetic enough to produce electron-positron pairs

neg: Lead glass glass, the former when struck absorbs more energy. This causes the lead crystal to oscillate, thereby producing its characteristic sound. Lead also increases the solubility of tin, copper, and antimony, leading to its use in colored enamels and glazes. The low viscosity of lead glass melt is the reason for typically high lead oxide content in the glass solders. The presence of lead is used in glasses absorbing gamma radiation and X-rays, used in radiation shielding (e.g. in cathode ray tubes, where lowering the exposure of the viewer to soft X-rays is of concern). The high ionic radius of the

neg: Gamma ray gamma decay is seen in the afterglow of certain supernovas, but radiation from high energy processes known to involve other radiation sources than radioactive decay is still classed as gamma radiation. For example, modern high-energy X-rays produced by linear accelerators for megavoltage treatment in cancer often have higher energy (4 to 25 MeV) than do most classical gamma rays produced by nuclear gamma decay. One of the most common gamma ray emitting isotopes used in diagnostic nuclear medicine, technetium-99m, produces gamma radiation of the same energy (140 keV) as that produced by diagnostic X-ray machines, but of significantly lower energy

neg: Mawrth Vallis minerals. The GRS is used to measure the abundance of elements on the surface of Mars. Gamma rays can be measured when cosmic rays hit the surface and cause elements to emit identifiable signatures of energy (gamma rays). Measuring these gamma rays allows for the calculation of various element abundances. Water has been inferred by calculating the abundance of hydrogen . The GRS is separated from the main body of Odyssey by a 20 ft boom to reduce interference caused by the orbiter. THEMIS detected hydrated minerals at Mawth Vallis and also provided images of a large outflow channel which

neg: Pair-instability supernova the positrons find electrons and the pressure from gamma rays is driven up, again. The population of positrons provides a brief reservoir of new gamma rays as the expanding supernova's core pressure drops. As temperatures and gamma ray energies increase, more and more gamma ray energy is absorbed in creating electron-positron pairs. This reduction in gamma ray energy density reduces the radiation pressure that resists gravitational collapse and supports the outer layers of the star. The star contracts, compressing and heating the core, thereby increasing the rate of energy production. This increases the energy of the gamma rays that are

neg: Electromagnetic spectrum X-rays, and gamma rays at the high-frequency (short wavelength) end. The electromagnetic waves in each of these bands have different characteristics, such as how they are produced, how they interact with matter, and their practical applications. The limit for long wavelengths is the size of the universe itself, while it is thought that the short wavelength limit is in the vicinity of the Planck length. Gamma rays, X-rays, and high ultraviolet are classified as "ionizing radiation" as their photons have enough energy to ionize atoms, causing chemical reactions. Exposure to these rays can be a health hazard, causing radiation sickness,

neg: Hulk (comics) the deal and flees with Banner's body, leaving his alter ego in the desert where he was created to ensure that Doctor Doom cannot use Banner's intellect. When Banner goes insane due to his separation from the Hulk, irradiating an entire tropical island trying to recreate his transformation- something he cannot do as the cloned body lacks the genetic elements of Banner that allowed him to process the gamma radiation- the Hulk is forced to destroy his other side by letting him be disintegrated by a gamma bomb, prompting the Hulk to accuse Doom of tampering with Banner's mind, only

neg: Electromagnetic radiation electromagnetic radiation, not particles, and in 1914 Rutherford and Edward Andrade measured their wavelengths, finding that they were similar to X-rays but with shorter wavelengths and higher frequency, although a 'cross-over' between X and gamma rays makes it possible to have X-rays with a higher energy (and hence shorter wavelength) than gamma rays and vice versa. The origin of the ray differentiates them, gamma rays tend to be a natural phenomena originating from the unstable nucleus of an atom and X-rays are electrically generated (and hence man-made) unless they are as a result of bremsstrahlung X-radiation caused by the interaction

neg: High Energy Stereoscopic System High Energy Stereoscopic System High Energy Stereoscopic System (H.E.S.S.) is a system of Imaging Atmospheric Cherenkov Telescopes (IACT) for the investigation of cosmic gamma rays in the photon energy range of 0.03 to 100 TeV. The acronym was chosen in honour of Victor Hess, who was the first to observe cosmic rays. The name also emphasizes two main features of the installation, namely the simultaneous observation of air showers with several telescopes, under different viewing angles, and the combination of telescopes to a large system to increase the effective detection area for gamma rays. H.E.S.S. permits the exploration of gamma-ray

neg: Gamma ray Gamma ray A gamma ray or gamma radiation (symbol γ or formula_1), is a penetrating electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves and so imparts the highest photon energy. Paul Villard, a French chemist and physicist, discovered gamma radiation in 1900 while studying radiation emitted by radium. In 1903, Ernest Rutherford named this radiation "gamma rays" based on their relatively strong penetration of matter; he had previously discovered two less penetrating types of decay radiation, which he named alpha rays and beta rays in ascending order of penetrating power.

neg: Gamma ray active galaxies are thought to have a gamma ray production source similar to a particle accelerator. High energy electrons produced by the quasar, and subjected to inverse Compton scattering, synchrotron radiation, or bremsstrahlung, are the likely source of the gamma rays from those objects. It is thought that a supermassive black hole at the center of such galaxies provides the power source that intermittently destroys stars and focuses the resulting charged particles into beams that emerge from their rotational poles. When those beams interact with gas, dust, and lower energy photons they produce X-rays and gamma rays. These sources are

neg: Hulk (comics) radiation Banner is exposed to at the initial blast would induce radiation sickness and kill him, or if not, create significant cancer risks for Banner, because hard radiation strips cells of their ability to function. They go on to offer up an alternate origin, in which a Hulk might be created by biological experimentation with adrenal glands and GFP. Charles Q. Choi from LiveScience.com further explains that unlike the Hulk, gamma rays are not green; existing as they do beyond the visible spectrum, gamma rays have no color at all that we can describe. He also explains that gamma rays

neg: Electromagnetic spectrum from charged alpha and beta particles) and Edward Andrade measured their wavelengths, and found that gamma rays were similar to X-rays, but with shorter wavelengths and higher frequencies. Electromagnetic waves are typically described by any of the following three physical properties: the frequency "f", wavelength λ, or photon energy "E". Frequencies observed in astronomy range from (1 GeV gamma rays) down to the local plasma frequency of the ionized interstellar medium (~1 kHz). Wavelength is inversely proportional to the wave frequency, so gamma rays have very short wavelengths that are fractions of the size of atoms, whereas wavelengths on the

neg: Los Rayos Gamma their wrongdoings and the parody itself on gamma rays (a pun on his current therapy against his illness). He then contacted friends Horacio Olivo, Silverio Pérez and Jacobo Morales to help him with the project. Morales had the idea of taking Eddie's written parodies and blending them with previously censored TV scripts to produce a political parody stage show. The initial title of the project was "El Efecto de los Rayos Gamma sobre Eddie López" ("The effect of gamma rays on Eddie López") which was a take on the title of Paul Zindel's play "The Effect of Gamma Rays on

neg: Irradiation Missouri, irradiation of seed and plant germplasm has resulted in creating many widely-grown cultivars of food crops worldwide. The process, which consists of striking plant seeds or germplasm with radiation in the form of X-rays, UV waves, heavy-ion beams, or gamma rays, essentially "mixes" the genes already existing in the genome. The UN has been an active participant through the International Atomic Energy Agency. Irradiation is also employed to prevent the sprouting of certain cereals, onions, potatoes and garlic. Appropriate irradiation doses are also used to produce insects for use in the sterile insect technique of pest control. The U.S.

neg: Gamma spectroscopy within the measuring period versus channel number. The spectrum indicates the following peaks (from left to right): The Compton distribution is a continuous distribution that is present up to channel 150 in Figure 1. The distribution arises because of primary gamma rays undergoing Compton scattering within the crystal: Depending on the scattering angle, the Compton electrons have different energies and hence produce pulses in different energy channels. If many gamma rays are present in a spectrum, Compton distributions can present analysis challenges. To reduce gamma rays, an anticoincidence shield can be used—"see Compton suppression". Gamma ray reduction techniques are especially

neg: Energetic Gamma Ray Experiment Telescope of the chamber to capture and record gamma rays, and finally a protective covering over the entire instrument. The chamber would manipulate the gamma ray into a way that it could be recorded. The sensor would capture and record the characteristics of the gamma ray. Finally, the protective covering would block out any unwanted energy rays. With the purpose of detecting individual gamma rays ranging from 30 MeV to 30 GeV, EGRET was equipped with a plastic scintillator anti-coincidence dome, spark chamber, and calorimeter. Starting from the outside of the telescope, scientists covered EGRET with a plastic scintillator anti-coincidence dome.

neg: Lunar Prospector important elements across the Moon. For example, the "Lunar Prospector" GRS identified several regions with high iron concentrations. The fundamental purpose of the GRS experiment was to provide global maps of elemental abundances on the lunar surface. The GRS was designed to record the spectrum of gamma rays emitted by: The most important elements detectable by the GRS were uranium (U), thorium (Th), and potassium (K), radioactive elements which generate gamma rays spontaneously, and iron (Fe), titanium (Ti), oxygen (O), silicon (Si), aluminum (Al), magnesium (Mg), and calcium (Ca), elements which emit gamma rays when hit by cosmic rays or

neg: Energetic Gamma Ray Experiment Telescope a thallium-activated sodium iodide (NaI(Tl)) calorimeter at its base. The calorimeter captured the resolution of the gamma rays that entered EGRET. Since NASA scientists wanted only certain types of gamma rays to be processed and recorded, they set up EGRET with many systems of checks to filter out any unwanted information. The most basic type of filter EGRET had was only allowing gamma rays entering the telescope from certain angles to be let into the spark chamber. As the gamma ray travelled through the spark chamber, it struck one of the metal plates within the spark chamber. Once the gamma

neg: Gamma ray of GeV photons using lasers as exciters through a controlled interplay between the cascade and anomalous radiative trapping. Thunderstorms can produce a brief pulse of gamma radiation called a terrestrial gamma-ray flash. These gamma rays are thought to be produced by high intensity static electric fields accelerating electrons, which then produce gamma rays by bremsstrahlung as they collide with and are slowed by atoms in the atmosphere. Gamma rays up to 100 MeV can be emitted by terrestrial thunderstorms, and were discovered by space-borne observatories. This raises the possibility of health risks to passengers and crew on aircraft flying in

neg: Antimatter rocket charged and uncharged pions, in addition to neutrinos and gamma rays. The charged pions can be channelled by a magnetic nozzle, producing thrust. This type of antimatter rocket is a pion rocket or beamed core configuration. It is not perfectly efficient; energy is lost as the rest mass of the charged (22.3%) and uncharged pions (14.38%), lost as the kinetic energy of the uncharged pions (which can't be deflected for thrust), and lost as neutrinos and gamma rays (see antimatter as fuel). Positron annihilation has also been proposed for rocketry. Annihilation of positrons produces only gamma rays. Early proposals for

neg: Gamma spectroscopy just as in optical spectroscopy, the optical spectrum is characteristic of the material contained in a sample. Gamma rays are the highest-energy form of electromagnetic radiation, being physically the same as all other forms (e.g., X rays, visible light, infrared, radio) but having (in general) higher photon energy due to their shorter wavelength. Because of this, the energy of gamma-ray photons can be resolved individually, and a gamma-ray spectrometer can measure and display the energies of the gamma-ray photons detected. Radioactive nuclei (radionuclides) commonly emit gamma rays in the energy range from a few keV to ~10 MeV, corresponding to

neg: History of chemistry and physicist Ernest Rutherford is considered to be "the father of nuclear physics." Rutherford is best known for devising the names alpha, beta, and gamma to classify various forms of radioactive "rays" which were poorly understood at his time (alpha and beta rays are particle beams, while gamma rays are a form of high-energy electromagnetic radiation). Rutherford deflected alpha rays with both electric and magnetic fields in 1903. Working with Frederick Soddy, Rutherford explained that radioactivity is due to the transmutation of elements, now known to involve nuclear reactions. He also observed that the intensity of radioactivity of a radioactive

neg: Paul Ulrich Villard Paul Ulrich Villard Paul Ulrich Villard (28 September 1860 – 13 January 1934) was a French chemist and physicist. He discovered gamma rays in 1900 while studying the radiation emanating from radium. Villard was born in Saint-Germain-au-Mont-d'Or, Rhône. He graduated from the École Normale Supérieure in 1881 and taught in several Lycées, ending with a Lycée in Montpellier. He would maintain a laboratory position at the Ecole Normale Supérieure until his retirement. At the time when he discovered what we now call gamma rays, Villard was working in the chemistry department of the École Normale Supérieure rue d'Ulm, Paris. Villard

neg: InterPlanetary Network be focused with mirrors. The rays penetrate mirror materials instead of reflecting. Because gamma rays cannot be focused into an image in the traditional sense, a unique location for a gamma ray source cannot be determined as it is done with less energetic light. In addition, gamma ray bursts are brief flashes (often as little as 0.2 seconds) that occur randomly across the sky. Some forms of gamma ray telescope can generate an image, but they require longer integration times, and cover only a fraction of the sky. Once three spacecraft detect a GRB, their timings are sent to the

neg: Iodine-131 606 keV (89% abundance, others 248–807 keV) and 364 keV gamma rays (81% abundance, others 723 keV). Beta decay also produces an antineutrino, which carries off variable amounts of the beta decay energy. The electrons, due to their high mean energy (190 keV, with typical beta-decay spectra present) have a tissue penetration of . Iodine in food is absorbed by the body and preferentially concentrated in the thyroid where it is needed for the functioning of that gland. When I is present in high levels in the environment from radioactive fallout, it can be absorbed through contaminated food, and will