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Isotopes Of Californium
Californium (Cf) is an artificial element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was Cf in 1950. There are 20 known radioisotopes ranging from Cf to Cf and one nuclear isomer, Cf. The longest-lived isotope is Cf with a half-life of 898 years. List of isotopes , -id=Californium-237 , rowspan=3, Cf , rowspan=3 style="text-align:right" , 98 , rowspan=3 style="text-align:right" , 139 , rowspan=3, 237.06220(10) , rowspan=3, 0.8(2) s , α (70%) , Cm , rowspan=3, 5/2+# , - , SF (30%) , (various) , - , β , Bk , -id=Californium-238 , rowspan=2, Cf , rowspan=2 style="text-align:right" , 98 , rowspan=2 style="text-align:right" , 140 , rowspan=2, 238.06149(32)# , rowspan=2, 21.1(13) ms , SFLightest nuclide known to undergo spontaneous fission as its main decay mode , (various) , rowspan=2, 0+ , - , α (<5%) , Cm , -id=Californium-239 , rowspan=2, Cf [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Californium
Californium is a synthetic chemical element; it has symbol Cf and atomic number 98. It was first synthesized in 1950 at Lawrence Berkeley National Laboratory (then the University of California Radiation Laboratory) by bombarding curium with alpha particles (helium-4 ions). It is an actinide element, the sixth transuranium element to be synthesized, and has the second-highest atomic mass of all elements that have been produced in amounts large enough to see with the naked eye (after einsteinium). It was named after the university and the U.S. state of California. Two crystalline forms exist at normal pressure: one above and one below . A third form exists at high pressure. Californium slowly tarnishes in air at room temperature. Californium compounds are dominated by the +3 oxidation state. The most stable of californium's twenty known isotopes is californium-251, with a half-life of 898 years. This short half-life means the element is not found in significant quantities in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neutron Cross-section
In nuclear physics, the concept of a neutron cross section is used to express the likelihood of interaction between an incident neutron and a target nucleus. The neutron cross section σ can be defined as the area in cm2 for which the number of neutron-nuclei reactions taking place is equal to the product of the number of incident neutrons that would pass through the area and the number of target nuclei. In conjunction with the neutron flux, it enables the calculation of the reaction rate, for example to derive the thermal power of a nuclear power plant. The standard unit for measuring the cross section is the barn, which is equal to 10−28 m2 or 10−24 cm2. The larger the neutron cross section, the more likely a neutron will react with the nucleus. An isotope (or nuclide) can be classified according to its neutron cross section and how it reacts to an incident neutron. Nuclides that tend to absorb a neutron and either decay or keep the neutron in its nucleus are neutron a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Department Of Homeland Security
The United States Department of Homeland Security (DHS) is the U.S. United States federal executive departments, federal executive department responsible for public security, roughly comparable to the Interior minister, interior, Home Secretary, home, or Ministry of Public Security, public security ministries in other countries. Its missions involve anti-terrorism, border security, civil defense, Immigration to the United States, immigration and customs, border security, border control, cyber security, cybersecurity, Airport security, transportation security, Maritime security (USCG), maritime security and Air-sea rescue, sea rescue, and the mitigation of Weapon of mass destruction, weapons of mass destruction. It began operations on March 1, 2003, after being formed as a result of the Homeland Security Act of 2002, enacted in response to the September 11 attacks. With more than 240,000 employees, DHS is the third-largest Cabinet of the United States, Cabinet department, after t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Guard (United States)
The National Guard is a U.S. state, state-based military force that becomes part of the United States Armed Forces, U.S. military's reserve components of the United States Armed Forces, reserve components of the United States Army, U.S. Army and the United States Air Force, U.S. Air Force when activated for federal missions.National Guard: FAQ . United States National Guard. Accessed February 2, 2022. It is a military reserve force composed of National Guard military members or units of each state, the territories of Guam National Guard, Guam, the Virgin Islands National Guard, U.S. Virgin Islands, Puerto Rico National Guard, Puerto Rico, and the District of Columbia National Guard, District of Columbia, for a total of 54 separate organizations. It is officially created under United States Congress, Cong ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Armed Forces
The United States Armed Forces are the Military, military forces of the United States. U.S. United States Code, federal law names six armed forces: the United States Army, Army, United States Marine Corps, Marine Corps, United States Navy, Navy, United States Air Force, Air Force, United States Space Force, Space Force, and the United States Coast Guard, Coast Guard. Since 1949, all of the armed forces, except the Coast Guard, have been permanently part of the United States Department of Defense. They form six of the eight uniformed services of the United States. Each of the different military services is assigned a role and domain. The Army conducts land operations. The Navy and Marine Corps conduct maritime operations, the Marine Corps specializing in amphibious and maritime littoral operations primarily for supporting the Navy. The Air Force conducts air operations. The Space Force conducts space operations. The Coast Guard is unique in that it specializes in maritime opera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Fuel
Nuclear fuel refers to any substance, typically fissile material, which is used by nuclear power stations or other atomic nucleus, nuclear devices to generate energy. Oxide fuel For fission reactors, the fuel (typically based on uranium) is usually based on the metal oxide; the oxides are used rather than the metals themselves because the oxide melting point is much higher than that of the metal and because it cannot burn, being already in the oxidized state. Uranium dioxide Uranium dioxide is a black semiconductor, semiconducting solid. It can be made by heating uranyl nitrate to form . : This is then converted by heating with hydrogen to form UO2. It can be made from Enriched uranium, enriched uranium hexafluoride by reacting with ammonia to form a solid called ammonium diuranate, . This is then heated (Calcination, calcined) to form and U3O8 which is then converted by heating with hydrogen or ammonia to form UO2. The UO2 is mixed with an organic binder and pressed in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Reactor
A nuclear reactor is a device used to initiate and control a Nuclear fission, fission nuclear chain reaction. They are used for Nuclear power, commercial electricity, nuclear marine propulsion, marine propulsion, Weapons-grade plutonium, weapons production and Research reactor, research. Fissile material, Fissile nuclei (primarily uranium-235 or plutonium-239) absorb single neutron, neutrons and split, releasing energy and multiple neutrons, which can induce further fission. Reactors stabilize this, regulating Neutron absorber, neutron absorbers and neutron moderator, moderators in the core. Fuel efficiency is exceptionally high; Enriched uranium#Low-enriched uranium (LEU), low-enriched uranium is 120,000 times more energy dense than coal. Heat from nuclear fission is passed to a working fluid Nuclear reactor#By coolant, coolant. In commercial reactors, this drives Turbine, turbines and electrical generator shafts. Some reactors are used for district heating, and isotopes, isoto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petrochemical
Petrochemicals (sometimes abbreviated as petchems) are the chemical products obtained from petroleum by refining. Some chemical compounds made from petroleum are also obtained from other fossil fuels, such as coal or natural gas, or renewable sources such as maize, palm fruit or sugar cane. The two most common petrochemical classes are olefins (including ethylene and propylene) and aromatics (including benzene, toluene and xylene isomers). Oil refineries produce olefins and aromatics by fluid catalytic cracking of petroleum fractions. Chemical plants produce olefins by steam cracking of natural gas liquids like ethane and propane. Aromatics are produced by catalytic reforming of naphtha. Olefins and aromatics are the building-blocks for a wide range of materials such as solvents, detergents, and adhesives. Olefins are the basis for polymers and oligomers used in plastics, resins, fibers, elastomers, lubricants, and gels. Global ethylene production was 190 milli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physics In Medicine And Biology
''Physics in Medicine & Biology'' is a biweekly peer-reviewed medical journal covering research on the application of physics to medicine, physiology, and biology. It was established in 1956 and is published by IOP Publishing on behalf of the Institute of Physics and Engineering in Medicine. It is also an official journal of the following medical societies: Canadian Organization of Medical Physics, Deutsche Gesellschaft für Medizinische Physik, Japanese Association of Radiological Physics, European Federation of Organisations for Medical Physics, and the International Organization for Medical Physics. The editor-in-chief is Katia Parodi (Ludwig Maximilian University of Munich). Abstracting and indexing The journal is abstracted and indexed in: *Inspec *Chemical Abstracts *BIOSIS Previews/Biological Abstracts *Compendex * Embase/Excerpta Medica * PASCAL *Science Citation Index *Current Contents *Index Medicus/MEDLINE/PubMed *VINITI Database RAS According to the ''Journal Cita ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electronvolt
In physics, an electronvolt (symbol eV), also written electron-volt and electron volt, is the measure of an amount of kinetic energy gained by a single electron accelerating through an Voltage, electric potential difference of one volt in vacuum. When used as a Units of energy, unit of energy, the numerical value of 1 eV in joules (symbol J) is equal to the numerical value of the Electric charge, charge of an electron in coulombs (symbol C). Under the 2019 revision of the SI, this sets 1 eV equal to the exact value Historically, the electronvolt was devised as a standard unit of measure through its usefulness in Particle accelerator#Electrostatic particle accelerators, electrostatic particle accelerator sciences, because a particle with electric charge ''q'' gains an energy after passing through a voltage of ''V''. Definition and use An electronvolt is the amount of energy gained or lost by a single electron when it moves through an Voltage, electric potential differenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neutron Source
A neutron source is any device that emits neutrons, irrespective of the mechanism used to produce the neutrons. Neutron sources are used in physics, engineering, medicine, nuclear weapons, petroleum exploration, biology, chemistry, and nuclear power. Neutron source variables include the energy of the neutrons emitted by the source, the rate of neutrons emitted by the source, the size of the source, the cost of owning and maintaining the source, and government regulations related to the source. Small devices Spontaneous fission Some isotopes undergo spontaneous fission (SF) with Neutron emission, emission of neutrons. The most common spontaneous fission source is the isotope californium-252. 252Cf and all other SF neutron sources are made by irradiating uranium or a Transuranium element, transuranic element in a nuclear reactor, where neutrons are absorbed in the starting material and its subsequent reaction products, transmuting the starting material into the SF isotope. 252Cf n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Branching Ratio
In particle physics and nuclear physics, the branching fraction (or branching ratio) for a decay is the fraction of particles which decay by an individual decay mode or with respect to the total number of particles which decay. It applies to either the radioactive decay of atoms or the decay of elementary particles. It is equal to the ratio of the partial decay constant of the decay mode to the overall decay constant. Sometimes a partial half-life is given, but this term is misleading; due to competing modes, it is not true that half of the particles will decay through a particular decay mode after its partial half-life. The partial half-life is merely an alternate way to specify the partial decay constant , the two being related through: :t_ = \frac. For example, for decays of Cs, 98.13% are ε (electron capture) or β (positron) decays, and 1.87% are β (electron) decays. The half-life of this isotope is 6.480 days, which corresponds to a total decay constant of 0.1070&nb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
