FACTOID # 1: Idaho produces more milk than Iowa, Indiana and Illinois combined.

 Home Encyclopedia Statistics States A-Z Flags Maps FAQ About

 WHAT'S NEW RELATED ARTICLES People who viewed "Beta decay" also viewed:

SEARCH ALL

Search encyclopedia, statistics and forums:

(* = Graphable)

Encyclopedia > Beta decay
Nuclear physics
Nuclear fission
Nuclear fusion
This box: view  talk  edit
Beta-minus (β-) decay. The intermediate emission of a W- boson is omitted.
The Feynman diagram for beta decay of a neutron into a proton, electron, and electron antineutrino via an intermediate heavy W- boson

In β decay, the weak interaction converts a neutron (n0) into a proton (p+) while emitting an electron (e) and an anti-neutrino ($bar{nu}_e$): The weak interaction (often called the weak force or sometimes the weak nuclear force) is one of the four fundamental interactions of nature. ... This article or section does not adequately cite its references or sources. ... For other uses, see Proton (disambiguation). ... Antineutrinos, the antiparticles of neutrinos, are neutral particles produced in nuclear beta decay. ...

 n0 → p+ + e- + νe

At the fundamental level (as depicted in the Feynman diagram below), this is due to the conversion of a down quark to an up quark by emission of a W- boson; the W- boson subsequently decays into an electron and an anti-neutrino. This article or section does not adequately cite its references or sources. ... For other uses, see Proton (disambiguation). ... For other uses, see Electron (disambiguation). ... Antineutrinos, the antiparticles of neutrinos, are neutral particles produced in nuclear beta decay. ... In particle physics, an elementary particle is a particle of which other, larger particles are composed. ... In this Feynman diagram, an electron and positron annihilate and become a quark-antiquark pair. ... The down quark is a first-generation quark with a charge of -(1/3)e. ... The up quark is a first-generation quark with a charge of +(2/3)e. ... In physics, the W and Z bosons are the elementary particles that mediate the weak nuclear force. ...

In β+ decay, energy is used to convert a proton into a neutron, a positron (e+ ) and a neutrino (νe): The first detection of the positron in 1932 by Carl D. Anderson The positron is the antiparticle or the antimatter counterpart of the electron. ... For other uses, see Neutrino (disambiguation). ...

 energy + p+ → n0 + e+ + νe

So, unlike beta minus decay, beta plus decay cannot occur in isolation, because it requires energy, the mass of the neutron being greater than the mass of the proton. Beta plus decay can only happen inside nuclei when the absolute value of the binding energy of the daughter nucleus is higher than that of the mother nucleus. The difference between these energies goes into the reaction of converting a proton into a neutron, a positron and a neutrino and into the kinetic energy of these particles. For other uses, see Proton (disambiguation). ... This article or section does not adequately cite its references or sources. ... The first detection of the positron in 1932 by Carl D. Anderson The positron is the antiparticle or the antimatter counterpart of the electron. ... For other uses, see Neutrino (disambiguation). ... For other uses, see Mass (disambiguation). ... Binding energy is the energy required to disassemble a whole into separate parts. ...

In all the cases where β+ decay is allowed energetically (and the proton is a part of a nucleus with electron shells), it is accompanied by the electron capture process, when an atomic electron is captured by a nucleus with the emission of a neutrino: Electron capture is a decay mode for isotopes that will occur when there are too many protons in the nucleus of an atom, and there isnt enough energy to emit a positron; however, it continues to be a viable decay mode for radioactive isotopes that can decay by positron...

 energy + p+ + e- → n0 + νe

But if the energy difference between initial and final states is low (less than 2mec2), then β+ decay is not energetically possible, and electron capture is the sole decay mode. For other uses, see Proton (disambiguation). ... For other uses, see Electron (disambiguation). ... This article or section does not adequately cite its references or sources. ... For other uses, see Neutrino (disambiguation). ... Electron capture is a decay mode for isotopes that will occur when there are too many protons in the nucleus of an atom, and there isnt enough energy to emit a positron; however, it continues to be a viable decay mode for radioactive isotopes that can decay by positron...

If the proton and neutron are part of an atomic nucleus, these decay processes transmute one chemical element into another. For example: The nucleus of an atom is the very small dense region, of positive charge, in its centre consisting of nucleons (protons and neutrons). ... // Transmutation is the conversion of one object into another. ...

 $color{blue}{}^{137}_{ 55},$ Cs → $color{blue}{}^{137}_{ 56},$ Ba + e- + νe (beta minus decay) $color{blue}{}^{22}_{11},$ Na → $color{blue}{}^{22}_{10},$ Ne + e+ + νe (beta plus decay) $color{blue}{}^{22}_{11},$ Na + e- → $color{blue}{}^{22}_{10},$ Ne + νe (electron capture)

Beta decay does not change the number of nucleons A in the nucleus but changes only its charge Z. Thus the set of all nuclides with the same A can be introduced; these isobaric nuclides may turn into each other via beta decay. Among them, several nuclides (at least one) are beta stable, because they present local minima of the mass excess: if such a nucleus has (A, Z) numbers, the neighbour nuclei (A, Z−1) and (A, Z+1) have higher mass excess and can beta decay into (A, Z), but not vice versa. It should be noted, that a beta-stable nucleus may undergo other kinds of radioactive decay (alpha decay, for example). In nature, most isotopes are beta stable, but a few exceptions exist with half-lives so long that they have not had enough time to decay since the moment of their nucleosynthesis. One example is 40K, which undergoes all three types of beta decay (beta minus, beta plus and electron capture) with a half life of 1.277×109 years. Caesium-137 is a radioactive isotope which is formed mainly by nuclear fission. ... General Name, Symbol, Number caesium, Cs, 55 Chemical series alkali metals Group, Period, Block 1, 6, s Appearance silvery gold Standard atomic weight 132. ... For other uses, see Barium (disambiguation). ... For other uses, see Electron (disambiguation). ... Antineutrinos, the antiparticles of neutrinos, are neutral particles produced in nuclear beta decay. ... For sodium in the diet, see Edible salt. ... Neon (Ne) Standard atomic mass: 20. ... For other uses, see Neon (disambiguation). ... The first detection of the positron in 1932 by Carl D. Anderson The positron is the antiparticle or the antimatter counterpart of the electron. ... For other uses, see Neutrino (disambiguation). ... For sodium in the diet, see Edible salt. ... For other uses, see Electron (disambiguation). ... Neon (Ne) Standard atomic mass: 20. ... For other uses, see Neon (disambiguation). ... For other uses, see Neutrino (disambiguation). ... In physics a nucleon is a collective name for two baryons: the neutron and the proton. ... This box:      Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. ... The word isobar derives from the two ancient Greek words, Î¹ÏƒÎ¿Ï‚ (isos), meaning equal, and Î²Î±ÏÎ¿Ï‚ (baros), meaning weight. In meteorology, thermodynamics, and similar science (and engineering), an isobar is a contour line of equal or constant pressure on a graph, plot, or map. ... Binding energy is the energy required to disassemble a whole into separate parts. ... Alpha decay Alpha decay is a type of radioactive decay in which an atom emits an alpha particle (two protons and two neutrons bound together into a particle identical to a helium nucleus) and transforms (or decays) into an atom with a mass number 4 less and atomic number 2... This article is about the computer game. ... Nucleosynthesis is the process of creating new atomic nuclei from preexisting nucleons (protons and neutrons). ... General Name, symbol, number potassium, K, 19 Chemical series alkali metals Group, period, block 1, 4, s Appearance silvery white Standard atomic weight 39. ...

Some nuclei can undergo double beta decay (ββ decay) where the charge of the nucleus changes by two units. In most practically interesting cases, single beta decay is energetically forbidden for such nuclei, because when β and ββ decays are both allowed, the probability of β decay is (usually) much higher, preventing investigations of very rare ββ decays. Thus, ββ decay is usually studied only for beta stable nuclei. Like single beta decay, double beta decay does not change A; thus, at least one of the nuclides with some given A has to be stable with regard to both single and double beta decay. In the process of beta decay unstable nuclei decay by converting a neutron in the nucleus to a proton and emitting an electron and anti-neutrino. ...

Beta decay can be considered as a perturbation as described in quantum mechanics, and thus follows Fermi's Golden Rule. In quantum physics, Fermis golden rule is a way to calculate the transition rate (probability of transition per unit time) from one energy eigenstate of a quantum system into a continuum of energy eigenstates, due to a perturbation. ...

Contents

A Kurie plot (also known as a Fermi-Kurie plot) is a graph used in studying beta decay, in which the square root of the number of beta particles whose momenta (or energy) lie within a certain narrow range, divided by a function worked out by Fermi, is plotted against beta-particle energy; it is a straight line for allowed transitions and some forbidden transitions, in accord with the Fermi beta-decay theory.

History

Historically, the study of beta decay provided the first physical evidence of the neutrino. In 1911 Lise Meitner and Otto Hahn performed an experiment that showed that the energies of electrons emitted by beta decay had a continuous rather than discrete spectrum. This was in apparent contradiction to the law of conservation of energy, as it appeared that energy was lost in the beta decay process. A second problem was that the spin of the Nitrogen-14 atom was 1, in contradiction to the Rutherford prediction of ½. For other uses, see Neutrino (disambiguation). ... Lise Meitner ca. ... Otto Hahn and Lise Meitner, 1913, at the KWI for Chemistry in Berlin Otto Hahn (March 8, 1879 â€“ July 28, 1968) was a German chemist and received the 1944 Nobel Prize in Chemistry. ... Conservation of energy (the first law of thermodynamics) is one of several conservation laws. ... Ernest Rutherford Ernest Rutherford, 1st Baron Rutherford of Nelson, PC, OM, FRS (August 30, 1871 â€“ October 19, 1937), was a New Zealand nuclear physicist. ...

In 1920-1927, Charles Drummond Ellis (along with James Chadwick and colleagues) established clearly that the beta decay spectrum is really continuous, ending all controversies. Sir Charles Drummond Ellis (b. ... Sir James Chadwick, CH (20 October 1891 â€“ 24 July 1974) was an English physicist and Nobel laureate who is best known for discovering the neutron. ...

In a famous letter written in 1930 Wolfgang Pauli suggested that in addition to electrons and protons atoms also contained an extremely light neutral particle which he called the neutron. He suggested that this "neutron" was also emitted during beta decay and had simply not yet been observed. In 1931 Enrico Fermi renamed Pauli's "neutron" to neutrino, and in 1934 Fermi published a very successful model of beta decay in which neutrinos were produced. This article is about the Austrian-Swiss physicist. ... Enrico Fermi (September 29, 1901 â€“ November 28, 1954) was an Italian physicist most noted for his work on the development of the first nuclear reactor, and for his contributions to the development of quantum theory, particle physics and statistical mechanics. ... For other uses, see Neutrino (disambiguation). ... In physics, Fermis interaction is an old explanation of the weak force, proposed by Enrico Fermi. ...

Making it simple to understand the concept of beta decay is generally represented in the following way:

 ${}^{A}_{Z},$ XN → ${}^{ A}_{Z+1},$ YN-1 + e- + νe (beta minus decay) ${}^{A}_{Z},$ XN → ${}^{ A}_{Z-1},$ YN+1 + e+ + νe (beta plus decay) ${}^{A}_{Z},$ XN + e- → ${}^{ A}_{Z-1},$ YN+1 + νe (electron capture)

Where X and Y represent the parent and daughter nuclei respectively, (A= mass number, Z= atomic number, N= number of neutrons). For other uses, see Electron (disambiguation). ... Antineutrinos, the antiparticles of neutrinos, are neutral particles produced in nuclear beta decay. ... The first detection of the positron in 1932 by Carl D. Anderson The positron is the antiparticle or the antimatter counterpart of the electron. ... For other uses, see Neutrino (disambiguation). ... For other uses, see Electron (disambiguation). ... For other uses, see Neutrino (disambiguation). ...

References

• Franz N. D. Kurie, J. R. Richardson, H. C. Paxton (March 1936). "The Radiations Emitted from Artificially Produced Radioactive Substances. I. The Upper Limits and Shapes of the β-Ray Spectra from Several Elements". Physical Review 49 (5): 368-381. doi:10.1103/PhysRev.49.368.
• F. N. D. Kurie (May 1948). "On the Use of the Kurie Plot". Physical Review 73 (10): 1207. doi:10.1103/PhysRev.73.1207.

Physical Review is one of the oldest and most-respected scientific journals publishing research on all aspects of physics. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ...

Results from FactBites:

 Beta decay - Wikipedia, the free encyclopedia (781 words) In nuclear physics, beta decay is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted. In nature, most isotopes are beta stable, but a few exceptions exist with half-lives so long that they have not had enough time to decay since the moment of their nucleosynthesis. Beta decay can be considered as a perturbation as described in quantum mechanics, and thus follows Fermi's Golden Rule.
 Double beta decay - Wikipedia, the free encyclopedia (415 words) In the process of beta decay unstable nuclei decay by converting a neutron in the nucleus to a proton and emitting an electron and anti-neutrino. In double beta decay two neutrons in the nuclei are converted to protons, and two electrons and two anti-neutrinos are emitted. In neutrinoless double beta decay the emitted neutrino is immediately absorbed (as its anti-particle) by another nucleon of the nucleus, so the total kinetic energy of the two electrons would be exactly the difference in binding energy between the initial and final state nuclei.
More results at FactBites »

Share your thoughts, questions and commentary here