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Detonation of a nuclear weapon involves bringing fissile material into its optimal supercritical state very rapidly. During part of this process, the assembly is supercritical, but not yet in an optimal state for a chain reaction. Free neutrons, in particular from spontaneous fissions, can cause the device to undergo a... | 1 | Fission Products + Nuclear Fission |
In a normal thermal reactor, tin-121m has a very low fission product yield; thus, this isotope is not a significant contributor to nuclear waste. Fast fission or fission of some heavier actinides will produce Sn at higher yields. For example, its yield from U-235 is 0.0007% per thermal fission and 0.002% per fast fissi... | 1 | Fission Products + Nuclear Fission |
Initially used to approximate chemical reaction rates, models of isotope fractionation are used throughout the physical sciences. In chemistry, the Urey–Bigeleisen–Mayer equation has been used to predict equilibrium isotope effects and interpret the distributions of isotopes and isotopologues within systems, especially... | 0 | Isotopes |
Caesium-134 is found in spent nuclear fuel but is not produced by nuclear weapon explosions, as it is only formed by neutron capture on stable Cs-133, which is only produced by beta decay of Xe-133 with a half-life of 3 days. Cs-134 has a half-life of 2 years and may be a major source of gamma radiation in the first 20... | 1 | Fission Products + Nuclear Fission |
Clumped isotopes present a distinct set of challenges for isotopic reference materials. By convention the clumped isotope composition of CO liberated from CaCO (Δ) and CH (Δ/ΔCH3DCH2D2CO for carbon dioxide and CH for methane. Standard isotopic reference materials are still required in clumped isotope analysis for measu... | 0 | Isotopes |
Within the Fallout videogame universe many Nuka-Cola flavors are created using less than ethical ways. In particular the flavor, Nuka Cola Quantum, has a distinctive bright blue glow that comes from the added Strontium-90. This was also the last flavor to be created by Nuka Cola before the Great War. | 1 | Fission Products + Nuclear Fission |
Measurement of the abundance of clumped isotopes (doubly substituted isotopologues) of gases has been used in the field of stable isotope geochemistry to trace equilibrium and kinetic processes in the environment inaccessible by analysis of singly substituted isotopologues alone.
Currently measured doubly substituted i... | 0 | Isotopes |
Strontium-90 is not quite as likely as caesium-137 to be released as a part of a nuclear reactor accident because it is much less volatile, but is probably the most dangerous component of the radioactive fallout from a nuclear weapon.
A study of hundreds of thousands of deciduous teeth, collected by Dr. Louise Reiss an... | 1 | Fission Products + Nuclear Fission |
In stable isotope geochemistry, the Urey–Bigeleisen–Mayer equation, also known as the Bigeleisen–Mayer equation or the Urey model, is a model describing the approximate equilibrium isotope fractionation in an isotope exchange reaction. While the equation itself can be written in numerous forms, it is generally presente... | 0 | Isotopes |
The earliest compelling evidence for human habitation of the Americas comes from the Clovis complex, between 11,050 and 10,800 C yr B.P. However, a series of human tracks were identified at White Sands National Park, New Mexico, which have been dated contentiously dated to between 23,000 and 21,000 years ago - during t... | 0 | Isotopes |
Selenium-79 is a radioisotope of selenium present in spent nuclear fuel and the wastes resulting from reprocessing this fuel. It is one of only 7 long-lived fission products. Its fission yield is low (about 0.04%), as it is near the lower end of the mass range for fission products. Its half-life has been variously repo... | 1 | Fission Products + Nuclear Fission |
Iodine-131 (I, I-131) is an important radioisotope of iodine discovered by Glenn Seaborg and John Livingood in 1938 at the University of California, Berkeley. It has a radioactive decay half-life of about eight days. It is associated with nuclear energy, medical diagnostic and treatment procedures, and natural gas prod... | 1 | Fission Products + Nuclear Fission |
It is now known from study of the Sun and primitive meteorites that the solar system was initially almost homogeneous in isotopic composition. Deviations from the (evolving) galactic average, locally sampled around the time that the Sun's nuclear burning began, can generally be accounted for by mass fractionation (see ... | 0 | Isotopes |
In general, most actinide isotopes with an odd neutron number are fissile. Most nuclear fuels have an odd atomic mass number ( = the total number of nucleons), and an even atomic number Z. This implies an odd number of neutrons. Isotopes with an odd number of neutrons gain an extra 1 to 2 MeV of energy from absorbing a... | 1 | Fission Products + Nuclear Fission |
After the detonation of a weapon at or above the fallout-free altitude (an air burst), fission products, un-fissioned nuclear material, and weapon residues vaporized by the heat of the fireball condense into a suspension of particles 10 nm to 20 µm in diameter. This size of particulate matter, lifted to the stratospher... | 1 | Fission Products + Nuclear Fission |
Isotope analysis has many applications in archaeology, from dating sites and artefacts, determination of past diets and migration patterns and for environmental reconstruction.
Information is determined by assessing the ratio of different isotopes of a particular element in a sample. The most widely studied and used is... | 0 | Isotopes |
Hot particles, radioactive particles of nuclear fallout and radioactive waste, also exhibit distinct isotopic signatures. Their radionuclide composition (and thus their age and origin) can be determined by mass spectrometry or by gamma spectrometry. For example, particles generated by a nuclear blast contain detectable... | 0 | Isotopes |
Initial measurements of position specific isotope enrichments were measured using isotope ratio mass spectrometry in which sites on a molecule were first degraded to , the was captured and purified, and then the CO was measured for its isotope composition on an Isotope Ratio Mass Spectrometer (IRMS). Py-GC-MS was also... | 0 | Isotopes |
Isotopic oxygen is incorporated into the body primarily through ingestion at which point it is used in the formation of, for archaeological purposes, bones and teeth. The oxygen is incorporated into the hydroxylcarbonic apatite of bone and tooth enamel.
Bone is continually remodelled throughout the lifetime of an indiv... | 0 | Isotopes |
An isotopic signature (also isotopic fingerprint) is a ratio of non-radiogenic stable isotopes, stable radiogenic isotopes, or unstable radioactive isotopes of particular elements in an investigated material. The ratios of isotopes in a sample material are measured by isotope-ratio mass spectrometry against an isotopic... | 0 | Isotopes |
The high short-term radioactivity of spent nuclear fuel is primarily from fission products with short half-life.
The radioactivity in the fission product mixture is mostly due to short-lived isotopes such as I and Ba, after about four months Ce, Zr/Nb and Sr constitute the largest contributors, while after about two or... | 1 | Fission Products + Nuclear Fission |
The first paper on site-specific enrichment used the ninhydrin reaction to cleave the carboxyl site off alpha-amino acids in photosynthetic organisms. The authors demonstrated an enriched carboxyl site relative to the bulk δC of the molecules, which they attribute to uptake of heavier CO through the Calvin cycle. A re... | 0 | Isotopes |
Many units of measurement were historically, or are still, defined with reference to the properties of specific substances that, in many cases, occurred in nature as mixes of multiple isotopes, for example:
Since samples taken from different natural sources can have subtly different isotopic ratios, the relevant proper... | 0 | Isotopes |
The purpose of radiological emergency preparedness is to protect people from the effects of radiation exposure after a nuclear accident or bomb. Evacuation is the most effective protective measure. However, if evacuation is impossible or even uncertain, then local fallout shelters and other measures provide the best pr... | 1 | Fission Products + Nuclear Fission |
Not all neutrons are emitted as a direct product of fission; some are instead due to the radioactive decay of some of the fission fragments. The neutrons that occur directly from fission are called "prompt neutrons", and the ones that are a result of radioactive decay of fission fragments are called "delayed neutrons".... | 1 | Fission Products + Nuclear Fission |
For technologically advanced states the gun-type method is now essentially obsolete, for reasons of efficiency and safety (discussed above).
The gun type method was largely abandoned by the United States as soon as the implosion technique was perfected, though it was retained in the specialised role of nuclear artille... | 1 | Fission Products + Nuclear Fission |
In the Acerinox accident of 1998, the Spanish recycling company Acerinox accidentally melted down a mass of radioactive caesium-137 that came from a gamma-ray generator. | 1 | Fission Products + Nuclear Fission |
This is a summary table from List of nuclides. Note that numbers are not exact and may change slightly in the future, as nuclides are observed to be radioactive, or new half-lives are determined to some precision. | 0 | Isotopes |
The "gun" method is roughly how the Little Boy weapon, which was detonated over Hiroshima, worked, using uranium-235 as its fissile material. In the Little Boy design, the U-235 "bullet" had a mass of around , and it was long, with a diameter of . The hollow cylindrical shape made it subcritical. It was powered by a c... | 1 | Fission Products + Nuclear Fission |
A boosted fission weapon usually refers to a type of nuclear bomb that uses a small amount of fusion fuel to increase the rate, and thus yield, of a fission reaction. The neutrons released by the fusion reactions add to the neutrons released due to fission, allowing for more neutron-induced fission reactions to take pl... | 1 | Fission Products + Nuclear Fission |
Long-lived fission products (LLFPs) are radioactive materials with a long half-life (more than 200,000 years) produced by nuclear fission of uranium and plutonium. Because of their persistent radiotoxicity, it is necessary to isolate them from humans and the biosphere and to confine them in nuclear waste repositories f... | 1 | Fission Products + Nuclear Fission |
Tritium is a radioactive isotope with a half-life of 12.355 years. Its main decay product is helium-3, which is among the nuclides with the largest cross-section for neutron capture. Therefore, periodically the weapon must have its helium waste flushed out and its tritium supply recharged. This is because any helium-3 ... | 1 | Fission Products + Nuclear Fission |
Carbon is present in all biological material including skeletal remains, charcoal and food residues and plays an integral role in the dating of materials, through radiocarbon dating. The ratio of different carbon isotopes naturally fluctuates over time, and, by analysing the composition of carbon dioxide (CO) in ancien... | 0 | Isotopes |
To be a useful fuel for nuclear fission chain reactions, the material must:
* Be in the region of the binding energy curve where a fission chain reaction is possible (i.e., above radium)
* Have a high probability of fission on neutron capture
* Release more than one neutron on average per neutron capture. (Enough of th... | 1 | Fission Products + Nuclear Fission |
Unlike other isotopic dating methods, the "daughter" in fission track dating is an effect in the crystal rather than a daughter isotope. Uranium-238 undergoes spontaneous fission decay at a known rate, and it is the only isotope with a decay rate that is relevant to the significant production of natural fission tracks;... | 1 | Fission Products + Nuclear Fission |
Alongside strontium, dietary calcium is deposited in bones teeth, however Ca is more readily deposited than Sr in humans and animals who consume primarily or exclusively plants. Therefore, the greater the Ca:Sr ratio in sample, the more herbivorous the animal was likely to be. | 0 | Isotopes |
If Germanium-75 is produced, it quickly decays to Arsenic. Germanium-76 is essentially stable, only decaying via extremely slow double beta decay to . | 1 | Fission Products + Nuclear Fission |
The 146 even-proton, even-neutron (EE) nuclides comprise ~58% of all stable nuclides and all have spin 0 because of pairing. There are also 24 primordial long-lived even-even nuclides. As a result, each of the 41 even-numbered elements from 2 to 82 has at least one stable isotope, and most of these elements have severa... | 0 | Isotopes |
The United States government, often the Office of Civil Defense in the Department of Defense, provided guides to fallout protection in the 1960s, frequently in the form of booklets. These booklets provided information on how to best survive nuclear fallout. They also included instructions for various fallout shelters, ... | 1 | Fission Products + Nuclear Fission |
IAEA issues official certificates of isotopic composition for most new calibration materials. The IAEA has certified isotopic values for [https://nucleus.iaea.org/rpst/Documents/VSMOW2_SLAP2.pdf VSMOW2/SLAP2] and [https://nucleus.iaea.org/rpst/referenceproducts/ReferenceMaterials/Stable_Isotopes/13C18and7Li/IAEA-603/RM... | 0 | Isotopes |
The count of 251 known stable nuclides includes tantalum-180m, since even though its decay and instability is automatically implied by its notation of "metastable", this has still not yet been observed. All "stable" isotopes (stable by observation, not theory) are the ground states of nuclei, with the exception of tant... | 0 | Isotopes |
Doubly labeled water may be administered by injection, or orally (the usual route in humans). Since the isotopes will be diluted in body water, there is no need to administer them in a state of high isotopic purity, no need to employ water in which all or even most atoms are heavy atoms, or even to begin with water whi... | 0 | Isotopes |
Caesium-137, along with other radioactive isotopes caesium-134, iodine-131, xenon-133, and strontium-90, were released into the environment during nearly all nuclear weapon tests and some nuclear accidents, most notably the Chernobyl disaster and the Fukushima Daiichi disaster.
Caesium-137 in the environment is substan... | 1 | Fission Products + Nuclear Fission |
The concept of isotopes developed from radioactivity. The pioneering work on radioactivity by Henri Becquerel, Marie Curie and Pierre Curie was awarded the [https://www.nobelprize.org/nobel_prizes/physics/laureates/1903/ Nobel Prize in Physics in 1903]. Later Frederick Soddy would take radioactivity from physics to che... | 0 | Isotopes |
After several years of cooling, most radioactivity is from the fission products caesium-137 and strontium-90, which are each produced in about 6% of fissions, and have half-lives of about 30 years. Other fission products with similar half-lives have much lower fission product yields, lower decay energy, and several (Sm... | 1 | Fission Products + Nuclear Fission |
Position-specific isotope analysis, also called site-specific isotope analysis, is a branch of isotope analysis aimed at determining the isotopic composition of a particular atom position in a molecule. Isotopes are elemental variants with different numbers of neutrons in their nuclei, thereby having different atomic m... | 0 | Isotopes |
Carbon label is a form of isotopic labeling where a carbon-12 atom is replaced with either a stable carbon-13 atom or radioactive carbon-11 or carbon-14 atoms in a chemical compound so as to tag (i.e. label) that position of the compound to assist in determining the way a chemical reaction proceeds i.e. the reaction me... | 0 | Isotopes |
Iodine-129 (I) is a long-lived radioisotope of iodine that occurs naturally but is also of special interest in the monitoring and effects of man-made nuclear fission products, where it serves as both a tracer and a potential radiological contaminant. | 1 | Fission Products + Nuclear Fission |
Antimony-125 decays with a half life of over two years to which itself decays with a half life of almost two months via isomeric transition to the ground state. While its relatively short half life and the significant gamma emissions (144.77 keV) of its daughter nuclide make usage in an RTG less attractive, Sb-125 cou... | 1 | Fission Products + Nuclear Fission |
Human domination of the biosphere has threatened global biodiversity, with uncertain consequences for ecosystems that provide food, clean air and water, and other valuable ecosystem services. Understanding the impacts of biodiversity loss on ecosystem function requires knowledge of the interactions between organisms wi... | 0 | Isotopes |
The most notable examples of mass-independent fractionation in nature are found in the isotopes of oxygen and sulfur. The first example was discovered by Robert N. Clayton, Toshiko Mayeda, and Lawrence Grossman in 1973, in the oxygen isotopic composition of refractory calcium–aluminium-rich inclusions in the Allende me... | 0 | Isotopes |
In 2012, a team of scientists used NMR spectroscopy to measure all of the position-specific carbon isotope abundances of glucose and other sugars. It was shown that the isotope abundances are heterogeneous. Different portions of the sugar molecules are used for biosynthesis based on the metabolic pathway an organism us... | 0 | Isotopes |
The proton:neutron ratio is not the only factor affecting nuclear stability. It depends also on evenness or oddness of its atomic number Z, neutron number N and, consequently, of their sum, the mass number A. Oddness of both Z and N tends to lower the nuclear binding energy, making odd nuclei, generally, less stable. T... | 0 | Isotopes |
Ötzi is a Neolithic man who, in 1991, was found in an Alpine glacier between Austria and Italy. Ötzi is exceptionally well preserved since his body was dehydrated and encapsulated in glacial ice. Radiocarbon dating gave an age of approximately 5,200 years old. TIMS, ICP-MS and gas mass spectrometry have all been appli... | 0 | Isotopes |
I decays with a half-life of 8.02 days with beta minus and gamma emissions. This isotope of iodine has 78 neutrons in its nucleus, while the only stable nuclide, I, has 74. On decaying, I most often (89% of the time) expends its 971 keV of decay energy by transforming into stable xenon-131 in two steps, with gamma deca... | 1 | Fission Products + Nuclear Fission |
Non-mononuclidic elements are marked with an asterisk, and the long-lived primordial radioisotope given. In two cases (indium and rhenium), the most abundant naturally occurring isotope is the mildly radioactive one, and in the case of europium, nearly half of it is.
# Beryllium-9
# Fluorine-19
# Sodium-23
# Aluminium-... | 0 | Isotopes |
Before the isotopes can be separated and a ratio can be determined, the desired component of the tissue must be isolated. Such components include collagen, carbonate and apatite. Each component requires different means of isolation, and methods must be further specialised to account for the varied levels of decay and c... | 0 | Isotopes |
Meteorological conditions greatly influence fallout, particularly local fallout. Atmospheric winds are able to bring fallout over large areas. For example, as a result of a Castle Bravo surface burst of a 15 Mt thermonuclear device at Bikini Atoll on March 1, 1954, a roughly cigar-shaped area of the Pacific extending o... | 1 | Fission Products + Nuclear Fission |
The effective neutron multiplication factor can be described using the product of six probability factors that describe a nuclear system. These factors, traditionally arranged chronologically with regards to the life of a neutron in a thermal reactor, include the probability of fast non-leakage , the fast fission fact... | 1 | Fission Products + Nuclear Fission |
Strontium-90 is a "bone seeker" that exhibits biochemical behavior similar to calcium, the next lighter group 2 element. After entering the organism, most often by ingestion with contaminated food or water, about 70–80% of the dose gets excreted. Virtually all remaining strontium-90 is deposited in bones and bone marro... | 1 | Fission Products + Nuclear Fission |
The next table gives the terrestrial isotope distributions for some elements. Some elements, such as phosphorus and fluorine, only exist as a single isotope, with a natural abundance of 100%. | 0 | Isotopes |
The abundances of multiply substituted isotopologues can also be affected by kinetic processes. As for singly substituted isotopologues, departures from thermodynamic equilibrium in a doubly-substituted species can implicate the presence of a particular reaction taking place. Photochemistry occurring in the atmosphere ... | 0 | Isotopes |
Isotopic mass data from [http://physics.nist.gov/PhysRefData/Compositions/ Atomic Weights and Isotopic Compositions] ed. J. S. Coursey, D. J. Schwab and R. A. Dragoset, National Institute of Standards and Technology (2005). | 0 | Isotopes |
A common treatment method for preventing iodine-131 exposure is by saturating the thyroid with regular, stable iodine-127, as an iodide or iodate salt. | 1 | Fission Products + Nuclear Fission |
Nuclear fission weapons require a mass of fissile fuel that is prompt supercritical.
For a given mass of fissile material the value of k can be increased by increasing the density. Since the probability per distance travelled for a neutron to collide with a nucleus is proportional to the material density, increasing th... | 1 | Fission Products + Nuclear Fission |
Caesium-137 reacts with water, producing a water-soluble compound (caesium hydroxide). The biological behaviour of caesium is similar to that of potassium and rubidium. After entering the body, caesium gets more or less uniformly distributed throughout the body, with the highest concentrations in soft tissue. However,... | 1 | Fission Products + Nuclear Fission |
Photodisintegration (also called phototransmutation) is a similar but different physical process, in which an extremely high energy gamma ray interacts with an atomic nucleus and causes it to enter an excited state, which immediately decays by emitting a subatomic particle. | 1 | Fission Products + Nuclear Fission |
A graph of fission product yield against the mass number of the fission fragments has two pronounced but fairly flat peaks, at around 90 to 100, and 130 to 140. With thermal neutrons, yields of fission products with mass between the peaks, such as Cd, Sn, Sn, Sn, Sb, Sn, and Sb are very low.
The higher the energy of th... | 1 | Fission Products + Nuclear Fission |
Archaeological materials, such as bone, organic residues, hair, or sea shells, can serve as substrates for isotopic analysis. Carbon, nitrogen and zinc isotope ratios are used to investigate the diets of past people; these isotopic systems can be used with others, such as strontium or oxygen, to answer questions about ... | 0 | Isotopes |
The original carbon isotope reference material was a Belemnite fossil from the PeeDee Formation in South Carolina, known as the Pee Dee Belemnite (PDB). This PDB standard was rapidly consumed and subsequently researchers used replacement standards such as PDB II and PDB III. The carbon isotope reference frame was later... | 0 | Isotopes |
While less rhodium than ruthenium and palladium is formed (around 3.6% yield), the mixture of fission products still contains a significant amount of this metal. Due to the high prices of ruthenium, rhodium, and palladium, some work has been done on the separation of these metals to enable them to be used at a later da... | 1 | Fission Products + Nuclear Fission |
Typical therapeutic doses of I-131 are between 2220 and 7400 megabecquerels (MBq). Because of this high radioactivity and because the exposure of stomach tissue to beta radiation would be high near an undissolved capsule, I-131 is sometimes administered to human patients in a small amount of liquid. Administration of t... | 1 | Fission Products + Nuclear Fission |
Isotope effects are recurring patterns in the partitioning of heavy and light isotopes across different chemical species or compounds, or between atomic sites within a molecule. These isotope effects can come about from a near infinite number of processes, but most of them can be narrowed down into two main categories,... | 0 | Isotopes |
Photofission is a process in which a nucleus, after absorbing a gamma ray, undergoes nuclear fission and splits into two or more fragments.
The reaction was discovered in 1940 by a small team of engineers and scientists operating the Westinghouse Atom Smasher at the company's Research Laboratories in Forest Hills, Pen... | 1 | Fission Products + Nuclear Fission |
The danger of radiation from fallout also decreases rapidly with time due in large part to the exponential decay of the individual radionuclides. A book by Cresson H. Kearny presents data showing that for the first few days after the explosion, the radiation dose rate is reduced by a factor of ten for every seven-fold... | 1 | Fission Products + Nuclear Fission |
Due to redox-disequilibrium, selenium could be very reluctant to abiotic chemical reduction and would be released from the waste (spent fuel or vitrified waste) as selenate (), a soluble Se(VI) species, not sorbed onto clay minerals. Without solubility limit and retardation for aqueous selenium, the dose of Se is compa... | 1 | Fission Products + Nuclear Fission |
During detonations of devices at ground level (surface burst), below the fallout-free altitude, or in shallow water, heat vaporizes large amounts of earth or water, which is drawn up into the radioactive cloud. This material becomes radioactive when it combines with fission products or other radio-contaminants, or when... | 1 | Fission Products + Nuclear Fission |
The position-specific isotope effect of an enzymatic reaction is expressed as the ratio of rate constants for a monoisotopic substrate and a substrate substituted with one rare isotope. For example, enzyme formate dehydrogenase catalyzes the reaction of formate and NAD+ to carbon dioxide and NADH. The hydrogen of forma... | 0 | Isotopes |
On scales greater than 10 years, fission products, chiefly Tc, again represent a significant proportion of the remaining, though lower radioactivity, along with longer-lived actinides like neptunium-237 and plutonium-242, if those have not been destroyed.
The most abundant long-lived fission products have total decay e... | 1 | Fission Products + Nuclear Fission |
Krypton-85 is produced in small quantities by the interaction of cosmic rays with stable krypton-84 in the atmosphere. Natural sources maintain an equilibrium inventory of about 0.09 PBq in the atmosphere. | 1 | Fission Products + Nuclear Fission |
If a graph of the mass or mole yield of fission products against the atomic number of the fragments is drawn then it has two peaks, one in the area zirconium through to palladium and one at xenon through to neodymium. This is because the fission event causes the nucleus to split in an asymmetric manner, as nuclei close... | 1 | Fission Products + Nuclear Fission |
There are two main considerations for the location of an explosion: height and surface composition. A nuclear weapon detonated in the air, called an air burst, produces less fallout than a comparable explosion near the ground. A nuclear explosion in which the fireball touches the ground pulls soil and other materials i... | 1 | Fission Products + Nuclear Fission |
Each fission of a parent atom produces a different set of fission product atoms. However, while an individual fission is not predictable, the fission products are statistically predictable. The amount of any particular isotope produced per fission is called its yield, typically expressed as percent per parent fission... | 1 | Fission Products + Nuclear Fission |
Xenon-135 (Xe) is an unstable isotope of xenon with a half-life of about 9.2 hours. Xe is a fission product of uranium and it is the most powerful known neutron-absorbing nuclear poison (2 million barns; up to 3 million barns under reactor conditions), with a significant effect on nuclear reactor operation. The ultimat... | 1 | Fission Products + Nuclear Fission |
Krypton-85 is used in arc discharge lamps commonly used in the entertainment industry for large HMI film lights as well as high-intensity discharge lamps. The presence of krypton-85 in discharge tube of the lamps can make the lamps easy to ignite. Early experimental krypton-85 lighting developments included a railroad ... | 1 | Fission Products + Nuclear Fission |
Because many isotopic reference materials are defined relative to one another using the δ notation, there are few constraints on the absolute isotopic ratios of reference materials. For dual-inlet and continuous flow mass spectrometry uncertainty in the raw isotopic ratio is acceptable because samples are often measure... | 0 | Isotopes |
Most naturally occurring nuclides are stable (about 251; see list at the end of this article), and about 35 more (total of 286) are known to be radioactive with sufficiently long half-lives (also known) to occur primordially. If the half-life of a nuclide is comparable to, or greater than, the Earth's age (4.5 billion ... | 0 | Isotopes |
On Friday, April 5 an emergency regime was introduced in the Russian city of Khabarovsk after a local resident accidentally discovered that radiation levels had jumped sharply in one of the industrial areas of the city. According to volunteers of the dosimetric control group, the dosimeter at the NP site showed up to... | 1 | Fission Products + Nuclear Fission |
Craig observed that δO and δH isotopic composition of cold meteoric water from sea ice in the Arctic and Antarctica are much more negative than that in warm meteoric water from the tropic. A correlation between temperature (T) and δO was proposed later in the 1970s. Such correlation is then applied to study surface tem... | 0 | Isotopes |
When a light isotope is replaced with a heavy isotope (e.g., C for C), the bond between the two atoms will vibrate more slowly, thereby lowering the zero-point energy of the bond and acting to stabilize the molecule. An isotopologue with a doubly substituted bond is therefore slightly more thermodynamically stable, whi... | 0 | Isotopes |
The Orbitrap is a high-resolution Fourier transform mass spectrometer that has recently been adapted to allow for site-specific analyses. Molecules introduced into the Orbitrap are fragmented, accelerated, and analyzed. Because the Orbitrap characterizes molecular masses by measuring oscillations at radio frequencies, ... | 0 | Isotopes |
Actinides with odd neutron number are generally fissile (with thermal neutrons), whereas those with even neutron number are generally not, though they are fissionable with fast neutrons. All observationally stable odd-odd nuclides have nonzero integer spin. This is because the single unpaired neutron and unpaired proto... | 0 | Isotopes |
Xe isotopes are also promising in tracing mantle dynamics in Earths evolution. The first explicit recognition of non-atmospheric Xe in terrestrial samples came from the analysis of CO-well gas in New Mexico, displaying an excess of I-derived or primitive source Xe and high content in Xe due to the decay of U. At presen... | 0 | Isotopes |
Several applications exist that capitalize on the properties of the various isotopes of a given element. Isotope separation is a significant technological challenge, particularly with heavy elements such as uranium or plutonium. Lighter elements such as lithium, carbon, nitrogen, and oxygen are commonly separated by ga... | 0 | Isotopes |
The doubly labeled water method is particularly useful for measuring average metabolic rate (field metabolic rate) over relatively long periods of time (a few days or weeks), in subjects for which other types of direct or indirect calorimetric measurements of metabolic rate would be difficult or impossible. For example... | 0 | Isotopes |
Nuclear fission produces fission products, as well as actinides from nuclear fuel nuclei that capture neutrons but fail to fission, and activation products from neutron activation of reactor or environmental materials. | 1 | Fission Products + Nuclear Fission |
A monoisotopic element is an element which has only a single stable isotope (nuclide). There are 26 such elements, as listed.
Stability is experimentally defined for chemical elements, as there are a number of stable nuclides with atomic numbers over ~40 which are theoretically unstable, but apparently have half-lives ... | 0 | Isotopes |
Some fission products decay with the release of delayed neutrons, important to nuclear reactor control.
Other fission products, such as xenon-135 and samarium-149, have a high neutron absorption cross section. Since a nuclear reactor must balance neutron production and absorption rates, fission products that absorb neu... | 1 | Fission Products + Nuclear Fission |
On December 11, 2008, the DOE-SC announced the selection of Michigan State University to design and establish FRIB.
The project earned Critical Decision 1 (CD-1) approval in September 2010 which established a preferred alternative and the associated established cost and schedule ranges.
On August 1, 2013, DOE-SC approv... | 0 | Isotopes |
When a fissile atom undergoes nuclear fission, it breaks into two or more fission fragments. Also, several free neutrons, gamma rays, and neutrinos are emitted, and a large amount of energy is released. The sum of the rest masses of the fission fragments and ejected neutrons is less than the sum of the rest masses of t... | 1 | Fission Products + Nuclear Fission |
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