“beta decay”的概念、定义、翻译、参考文献-科学参考

beta decay

Physics

A type of weak interaction (see fundamental interactions) in which an unstable atomic nucleus changes into a nucleus of the same nucleon number (A) but different proton number (Z). There are three types of beta decay: negative beta decay, positive beta decay, and electron capture.

Negative beta decay:

${}_{Z}^{A}X \to {}_{Z + 1}^{A}Y + {}_{- 1}^{0}e + {}_{0}^{0}{\bar{υ}}$

A neutron in the nucleus X has decayed into a proton forming a new nucleus Y with the emission of an electron and antineutrino. This process involves a decrease in mass and is energetically favourable; it can also occur outside the nucleus—free neutrons decay with a mean lifetime of about 15 minutes.

Positive beta decay:

${}_{Z}^{A}X \to {}_{Z - 1}^{A}Y + {}_{1}^{0}e + {}_{0}^{0}υ$

A proton in the nucleus X transforms into a neutron and a new nucleus Y is formed with the emission of an antimatter electron (positron) and neutrino. This process involves an effective increase in mass for the proton and is not energetically favourable. It cannot occur outside the nucleus—free protons do not undergo this kind of interaction. The process is allowed within the environment of the nucleus because when the nucleus as a whole is taken into account the interaction represents an overall decrease in energy.

Electron capture:

${}_{Z}^{A}X + {}_{- 1}^{0}e → {}_{z - 1}^{A}Y + {}_{0}^{0}υ$

A proton in the nucleus X captures an electron from the atomic environment and becomes a neutron, emitting a neutrino in the process. This process also involves an effective increase in mass for the proton and is not energetically favourable; again, it cannot also occur outside the nucleus—free protons do not undergo this kind of interaction. The process is allowed within the environment of the nucleus because, taking into account the whole nucleus, the interaction represents an overall decrease in energy.

Astronomy

Radioactive decay in which an atomic nucleus spontaneously decays into a daughter nucleus, releasing two subatomic particles. Either a neutron turns into a proton, releasing an electron plus an antineutrino; or a proton turns into a neutron, releasing a positron plus a neutrino. The resultant nucleus has the same mass number as the original nucleus (i.e. the same total number of protons and neutrons), but the atomic number differs by one. The electrons or positrons emitted are known as beta particles.

Chemistry

A type of radioactive decay in which an unstable atomic nucleus changes into a nucleus of the same mass number but different proton number. The change involves the conversion of a neutron into a proton with the emission of an electron and an antineutrino $(n \to p + e^{-} + \bar{ν})$ or of a proton into a neutron with the emission of a positron and a neutrino (p → n + e⁺ + ν‎). An example is the decay of carbon–14:
${}_{6}^{14}C \to {}_{7}^{14}N + e^{-} + \bar{ν}$
The electrons or positrons emitted are called beta particles and streams of beta particles are known as beta radiation.

Chemical Engineering

The spontaneous emission of negatively charged electrons or beta particles by a heavy radioactive element. The radioactive decay results in the original element being gradually converted into another element. For example, the radioactive isotope of lead-210 loses a beta particle to give a radioactive isotope of bismuth-210. Beta decay may occur at the same time as decay of alpha particles.

Geology and Earth Sciences

Some unstable atoms decay by emitting a negatively charged beta particle (negatron) from the nucleus, often accompanied by the emission of radiant energy (gamma rays). Beta decay may be regarded as the alteration of a neutron into a proton and an electron. As a result of beta decay the atomic number of the atom is increased by one, while the neutron number is decreased by one.

单词	beta decay
释义	beta decay Physics A type of weak interaction (see fundamental interactions) in which an unstable atomic nucleus changes into a nucleus of the same nucleon number (A) but different proton number (Z). There are three types of beta decay: negative beta decay, positive beta decay, and electron capture. Negative beta decay: ${}_{Z}^{A}X \to {}_{Z + 1}^{A}Y + {}_{- 1}^{0}e + {}_{0}^{0}{\bar{υ}}$ A neutron in the nucleus X has decayed into a proton forming a new nucleus Y with the emission of an electron and antineutrino. This process involves a decrease in mass and is energetically favourable; it can also occur outside the nucleus—free neutrons decay with a mean lifetime of about 15 minutes. Positive beta decay: ${}_{Z}^{A}X \to {}_{Z - 1}^{A}Y + {}_{1}^{0}e + {}_{0}^{0}υ$ A proton in the nucleus X transforms into a neutron and a new nucleus Y is formed with the emission of an antimatter electron (positron) and neutrino. This process involves an effective increase in mass for the proton and is not energetically favourable. It cannot occur outside the nucleus—free protons do not undergo this kind of interaction. The process is allowed within the environment of the nucleus because when the nucleus as a whole is taken into account the interaction represents an overall decrease in energy. Electron capture: ${}_{Z}^{A}X + {}_{- 1}^{0}e → {}_{z - 1}^{A}Y + {}_{0}^{0}υ$ A proton in the nucleus X captures an electron from the atomic environment and becomes a neutron, emitting a neutrino in the process. This process also involves an effective increase in mass for the proton and is not energetically favourable; again, it cannot also occur outside the nucleus—free protons do not undergo this kind of interaction. The process is allowed within the environment of the nucleus because, taking into account the whole nucleus, the interaction represents an overall decrease in energy. Astronomy Radioactive decay in which an atomic nucleus spontaneously decays into a daughter nucleus, releasing two subatomic particles. Either a neutron turns into a proton, releasing an electron plus an antineutrino; or a proton turns into a neutron, releasing a positron plus a neutrino. The resultant nucleus has the same mass number as the original nucleus (i.e. the same total number of protons and neutrons), but the atomic number differs by one. The electrons or positrons emitted are known as beta particles. Chemistry A type of radioactive decay in which an unstable atomic nucleus changes into a nucleus of the same mass number but different proton number. The change involves the conversion of a neutron into a proton with the emission of an electron and an antineutrino $(n \to p + e^{-} + \bar{ν})$ or of a proton into a neutron with the emission of a positron and a neutrino (p → n + e⁺ + ν‎). An example is the decay of carbon–14: ${}_{6}^{14}C \to {}_{7}^{14}N + e^{-} + \bar{ν}$ The electrons or positrons emitted are called beta particles and streams of beta particles are known as beta radiation. Chemical Engineering The spontaneous emission of negatively charged electrons or beta particles by a heavy radioactive element. The radioactive decay results in the original element being gradually converted into another element. For example, the radioactive isotope of lead-210 loses a beta particle to give a radioactive isotope of bismuth-210. Beta decay may occur at the same time as decay of alpha particles. Geology and Earth Sciences Some unstable atoms decay by emitting a negatively charged beta particle (negatron) from the nucleus, often accompanied by the emission of radiant energy (gamma rays). Beta decay may be regarded as the alteration of a neutron into a proton and an electron. As a result of beta decay the atomic number of the atom is increased by one, while the neutron number is decreased by one.
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