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Giant Resonance
In nuclear physics, giant resonance is a high-frequency collective excitation of atomic nuclei, as a property of many-body quantum systems. In the macroscopic interpretation of such an excitation in terms of an oscillation, the most prominent giant resonance is a collective oscillation of all protons against all neutrons in a nucleus. In 1947, G. C. Baldwin and G. S. Klaiber observed the giant dipole resonance (GDR) in photonuclear reactions, and in 1972 the giant quadrupole resonance (GQR) was discovered, and in 1977 the giant monopole resonance (GMR) was discovered in medium and heavy nuclei.Chomaz, section 2.2.2.1 Giant dipole resonance Giant dipole resonances may result in a number of de-excitation events, such as nuclear fission, emission of neutrons or gamma rays, or combinations of these. Giant dipole resonances can be caused by any mechanism that imparts enough energy to the nucleus. Classical causes are irradiation with gamma rays at energies from 7 to 40 MeV, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Physics
Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions, in addition to the study of other forms of nuclear matter. Nuclear physics should not be confused with atomic physics, which studies the atom as a whole, including its electrons. Discoveries in nuclear physics have led to applications in many fields such as nuclear power, nuclear weapons, nuclear medicine and magnetic resonance imaging, industrial and agricultural isotopes, ion implantation in materials engineering, and radiocarbon dating in geology and archaeology. Such applications are studied in the field of nuclear engineering. Particle physics evolved out of nuclear physics and the two fields are typically taught in close association. Nuclear astrophysics, the application of nuclear physics to astrophysics, is crucial in explaining the inner workings of stars and the origin of the chemical elements. History The history of nuclear physics as a discipline ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Fission
Nuclear fission is a reaction in which the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons, and releases a very large amount of energy even by the energetic standards of radioactive decay. Nuclear fission was discovered by chemists Otto Hahn and Fritz Strassmann and physicists Lise Meitner and Otto Robert Frisch. Hahn and Strassmann proved that a fission reaction had taken place on 19 December 1938, and Meitner and her nephew Frisch explained it theoretically in January 1939. Frisch named the process "fission" by analogy with biological fission of living cells. In their second publication on nuclear fission in February 1939, Hahn and Strassmann predicted the existence and liberation of additional neutrons during the fission process, opening up the possibility of a nuclear chain reaction. For heavy nuclides, it is an exothermic reaction which can release large amounts of energy both as electromagnetic radiat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
McGraw-Hill Encyclopedia Of Science & Technology
The ''McGraw-Hill Encyclopedia of Science & Technology'' is an English-language multivolume encyclopedia, specifically focused on scientific and technical subjects, and published by McGraw-Hill Education. The most recent edition in print is the eleventh edition, copyright 2012 (), comprising twenty volumes. The encyclopedia covers the life sciences and physical sciences, as well as engineering and technology Technology is the application of Conceptual model, conceptual knowledge to achieve practical goals, especially in a reproducible way. The word ''technology'' can also mean the products resulting from such efforts, including both tangible too ... topics. There is also a one-volume ''McGraw-Hill Concise Encyclopedia of Science and Technology'' based on the full set. The sixth edition was published in May 2009 in twenty volumes including the "Index" (). Further "Concise" editions for Chemistry or Engineering are available today. The references work has been mentioned and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
David M
David (; , "beloved one") was a king of ancient Israel and Judah and the third king of the United Monarchy, according to the Hebrew Bible and Old Testament. The Tel Dan stele, an Aramaic-inscribed stone erected by a king of Aram-Damascus in the late 9th/early 8th centuries BCE to commemorate a victory over two enemy kings, contains the phrase (), which is translated as " House of David" by most scholars. The Mesha Stele, erected by King Mesha of Moab in the 9th century BCE, may also refer to the "House of David", although this is disputed. According to Jewish works such as the '' Seder Olam Rabbah'', '' Seder Olam Zutta'', and '' Sefer ha-Qabbalah'' (all written over a thousand years later), David ascended the throne as the king of Judah in 885 BCE. Apart from this, all that is known of David comes from biblical literature, the historicity of which has been extensively challenged,Writing and Rewriting the Story of Solomon in Ancient Israel; by Isaac Kalimi; page 3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angela Bracco
Angela Bracco (born 1955) is an Italian experimental nuclear physicist whose research has applied gamma spectroscopy to the study of nuclear structure. She is a professor of physics at the University of Milan, the president of the Italian Physical Society, and the president of the , a physics museum and research center in Rome. Education and career Bracco was born in 1955 in Lecco. She earned a laurea (then the equivalent of a master's degree) in 1979 from the University of Milan, and completed a Ph.D. in 1983 in Canada, through a joint program of the TRIUMF national particle accelerator center in Vancouver and the University of Manitoba in Winnipeg. She returned to the University of Milan as an assistant professor in 1983. She was promoted to associate professor in 1988 and full professor in 2002. She became president of the Italian Physical Society in 2000, and president of the Centro Ricerche Enrico Fermi in 2024. Book Bracco is a coauthor of the book ''Giant Resonances: Nuc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adriaan Van Der Woude
Adriaan van der Woude (3 June 1930, Westerbroek – 20 August 2017) was a Dutch nuclear physicist, known as a leading expert on giant resonances. Education and career He matriculated in 1948 at the University of Groningen, where he graduated in 1954 with s M.Sc. equivalent and in 1960 with a Ph.D. His doctoral dissertation ''Construction and operation of betatron and cloud chamber'' was supervised by Hendrik "Henk" Brinkmann (1909–1994). Van der Woude worked from 1960 to 1963 in Brinkmann's group at the University of Groningen's Physics Laboratory. From 1963 to 1965 he was on a leave of absence from the University of Groningen and did research at Oak Ridge National Laboratory on nuclear and atomic physics. He was employed from 1965 to August 1967 at the University of Groningen, from 1967 to 1972 as a staff member at Oak Ridge National Laboratory, and from 1972 as a senior scientist at the University of Groningen's newly established ''Kernfysisch Versneller Instituut'' (KVI Gronin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neutron Emission
Neutron emission is a mode of radioactive decay in which one or more neutrons are ejected from a Atomic nucleus, nucleus. It occurs in the most neutron-rich/proton-deficient nuclides, and also from excited states of other nuclides as in photodisintegration, photoneutron emission and beta-delayed neutron emission. As only a neutron is lost by this process the number of protons remains unchanged, and an atom does not become an atom of a different element, but a different isotope of the same element. Neutrons are also produced in the spontaneous fission, spontaneous and nuclear fission, induced fission of certain heavy nuclides. Spontaneous neutron emission As a consequence of the Pauli exclusion principle, nuclei with an excess of protons or neutrons have a higher average energy per nucleon. Nuclei with a sufficient excess of neutrons have a greater energy than the combination of a free neutron and a nucleus with one less neutron, and therefore can decay by neutron emission. Nuclei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internal Conversion
Internal conversion is an atomic decay process where an excited nucleus interacts electromagnetically with one of the orbital electrons of an atom. This causes the electron to be emitted (ejected) from the atom. Thus, in internal conversion (often abbreviated IC), a high-energy electron is emitted from the excited atom, but not from the nucleus. For this reason, the high-speed electrons resulting from internal conversion are not called beta particles, since the latter come from beta decay, where they are newly created in the nuclear decay process. IC is possible whenever gamma decay is possible, except if the atom is fully ionized. In IC, the atomic number does not change, and thus there is no transmutation of one element to another. Also, neutrinos and the weak force are not involved in IC. Since an electron is lost from the atom, a hole appears in an electron aura which is subsequently filled by other electrons that descend to the empty, yet lower energy level, and in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma Decay
Gamma (; uppercase , lowercase ; ) is the third letter of the Greek alphabet. In the system of Greek numerals it has a value of 3. In Ancient Greek, the letter gamma represented a voiced velar stop . In Modern Greek, this letter normally represents a voiced velar fricative , except before either of the two front vowels (/e/, /i/), where it represents a Voiced palatal fricative#Palatal, voiced palatal fricative ; while /g/ in foreign words is instead commonly transcribed as γκ). In the International Phonetic Alphabet and other modern Latin-alphabet based phonetic transcription#Alphabetic, phonetic notations, it represents the voiced velar fricative. History The Greek letter Gamma Γ is a grapheme derived from the Phoenician alphabet, Phoenician letter (''gīml'') which was rotated from the right-to-left script of Canaanite to accommodate the Greek language's writing system of left-to-right. The Canaanite grapheme represented the /g/ phoneme in the Canaanite language, and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma Ray
A gamma ray, also known as gamma radiation (symbol ), is a penetrating form of electromagnetic radiation arising from high energy interactions like the radioactive decay of atomic nuclei or astronomical events like solar flares. It consists of the shortest wavelength electromagnetic waves, typically shorter than those of X-rays. With frequencies above 30 exahertz () and wavelengths less than 10 picometers (), gamma ray photons have the highest photon energy of any form of electromagnetic radiation. 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; in 1900, he had already named two less penetrating types of decay radiation (discovered by Henri Becquerel) alpha rays and beta rays in ascending order of penetrating power. Gamma rays from radioactive decay are in the energy range ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Monopole
In particle physics, a magnetic monopole is a hypothetical particle that is an isolated magnet with only one magnetic pole (a north pole without a south pole or vice versa). A magnetic monopole would have a net north or south "magnetic charge". Modern interest in the concept stems from high-energy physics, particle theories, notably the grand unified theory, grand unified and superstring theory, superstring theories, which predict their existence. The known elementary particles that have electric charge are electric monopoles. Magnetism in bar magnets and electromagnets is not caused by magnetic monopoles, and indeed, there is no known experimental or observational evidence that magnetic monopoles exist. A magnetic monopole is not necessarily an elementary particle, and models for magnetic monopole production can include (but are not limited to) Spin (physics), spin-0 monopoles or spin-1 massive vector mesons. The term "magnetic monopole" only refers to the nature of the particle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Excited State
In quantum mechanics Quantum mechanics is the fundamental physical Scientific theory, theory that describes the behavior of matter and of light; its unusual characteristics typically occur at and below the scale of atoms. Reprinted, Addison-Wesley, 1989, It is ..., an excited state of a system (such as an atom, molecule or Atomic nucleus, nucleus) is any quantum state of the system that has a higher energy than the ground state (that is, more energy than the absolute minimum). Excitation refers to an increase in energy level above a chosen starting point, usually the ground state, but sometimes an already excited state. The temperature of a group of particles is indicative of the level of excitation (with the notable exception of systems that exhibit negative temperature). The lifetime of a system in an excited state is usually short: Spontaneous emission, spontaneous or stimulated emission, induced emission of a quantum of energy (such as a photon or a phonon) usually ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
