Elektronmagvonzatás

Elektronmagvonzatás, often translated as electron capture, is a type of radioactive decay in which an atomic nucleus absorbs an inner orbital electron. This process is a form of beta decay. When an electron is captured by the nucleus, it combines with a proton to form a neutron. This conversion results in the emission of an electron neutrino. The atomic number of the atom decreases by one, while its mass number remains unchanged.

This decay mode is typically observed in nuclei that are proton-rich, meaning they have an excess of protons relative to neutrons. For such isotopes, electron capture is energetically favorable compared to positron emission, another form of beta decay that also reduces the proton-to-neutron ratio. The captured electron is usually from the innermost electron shell, the K-shell, hence electron capture is sometimes referred to as K-capture. However, electrons from other inner shells can also be captured.

The process of electron capture leads to the formation of a vacancy in the electron shell from which the electron was captured. This vacancy is then filled by an electron from a higher energy shell. As the electron transitions to the lower energy level, it emits either an X-ray photon or an Auger electron. These emitted X-rays or Auger electrons are characteristic of the element formed after the decay and can be used for identification.

Examples of isotopes that undergo electron capture include Potassium-40, which decays to Argon-40, and Vanadium-49, which decays to Titanium-49. Electron capture plays a significant role in various fields, including astrophysics, where it is crucial for understanding stellar evolution and nucleosynthesis, and in medical imaging, where certain radioisotopes used in diagnostics decay via this mechanism.