“pair production”的概念、定义、翻译、参考文献-科学参考

pair production

Physics

The creation of an electron and a positron from a photon in a strong electric field, such as that surrounding an atomic nucleus. The electron and the positron each have a mass of about 9×10⁻³¹ kg, which is equivalent on the basis of the mass–energy equation (E=mc²) to a total of 16×10⁻¹⁴ J. The frequency, ν‎, associated with a photon of this energy (according to E=hν‎) is 2.5×10²⁰ Hz. Pair production thus requires photons of high quantum energy (Bremsstrahlung or gamma rays). Any excess energy is taken up as kinetic energy of the products. At higher energies it is possible to have pair production of heavier particles and their antiparticles.

Astronomy

The production of a particle and its antiparticle. This can happen in several ways. For example, an electron–positron pair can be produced from a gamma-ray photon of energy greater than 1.022 MeV in the electric field surrounding an atomic nucleus, or the pair may be produced by the collision of two photons whose total energy exceeds 1.022 MeV. The energies of photons in the early Big Bang were high enough to produce many varieties of pairs of particles. Protons and antiprotons could be produced during the first 2 × 10⁻⁶ s after the Big Bang when the temperature exceeded 10¹³ K, and positive and negative muon pairs until about 2 × 10⁻⁴ s. Electrons and positrons could be produced until the temperature fell below 10¹⁰ K, about 2 s after the Big Bang. Pair production is also important in secondary cosmic-ray showers.

单词	pair production
释义	pair production Physics The creation of an electron and a positron from a photon in a strong electric field, such as that surrounding an atomic nucleus. The electron and the positron each have a mass of about 9×10⁻³¹ kg, which is equivalent on the basis of the mass–energy equation (E=mc²) to a total of 16×10⁻¹⁴ J. The frequency, ν‎, associated with a photon of this energy (according to E=hν‎) is 2.5×10²⁰ Hz. Pair production thus requires photons of high quantum energy (Bremsstrahlung or gamma rays). Any excess energy is taken up as kinetic energy of the products. At higher energies it is possible to have pair production of heavier particles and their antiparticles. Astronomy The production of a particle and its antiparticle. This can happen in several ways. For example, an electron–positron pair can be produced from a gamma-ray photon of energy greater than 1.022 MeV in the electric field surrounding an atomic nucleus, or the pair may be produced by the collision of two photons whose total energy exceeds 1.022 MeV. The energies of photons in the early Big Bang were high enough to produce many varieties of pairs of particles. Protons and antiprotons could be produced during the first 2 × 10⁻⁶ s after the Big Bang when the temperature exceeded 10¹³ K, and positive and negative muon pairs until about 2 × 10⁻⁴ s. Electrons and positrons could be produced until the temperature fell below 10¹⁰ K, about 2 s after the Big Bang. Pair production is also important in secondary cosmic-ray showers.
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