Beta-decay

Beta decay is a type of radioactive decay in which a beta particle is emitted from an atomic nucleus. This process allows the atom to move closer to a stable configuration. Beta decay is classified into two types: beta-minus (β−) decay and beta-plus (β+) decay, also known as positron emission. Understanding beta decay is crucial in fields such as nuclear physics, nuclear medicine, and radiometric dating.

Beta-minus Decay

In beta-minus (β−) decay, a neutron in the nucleus is transformed into a proton, an electron (the beta particle in this case), and an antineutrino. The equation for β− decay is:

\[ n \rightarrow p^+ + e^- + \bar{\nu}_e \]

where \(n\) is a neutron, \(p^+\) is a proton, \(e^-\) is an electron, and \(\bar{\nu}_e\) is an antineutrino. This process increases the atomic number of the atom by one but leaves the atomic mass virtually unchanged.

Beta-plus Decay

Beta-plus decay, or positron emission, occurs when a proton in an atomic nucleus is converted into a neutron, a positron (the beta particle in this case), and a neutrino. The equation for β+ decay is:

\[ p^+ \rightarrow n + e^+ + \nu_e \]

where \(p^+\) is a proton, \(n\) is a neutron, \(e^+\) is a positron, and \(\nu_e\) is a neutrino. This process decreases the atomic number by one.

Electron Capture

Another process closely related to beta-plus decay is electron capture. In electron capture, an inner orbital electron is captured by the nucleus, combining with a proton to form a neutron and emitting a neutrino. Electron capture also decreases the atomic number by one but does not emit a positron.

Applications and Importance

Beta decay plays a significant role in many areas of science and technology. In nuclear medicine, beta emitters are used in radiotherapy to treat various diseases, including cancer. In nuclear physics, understanding beta decay is essential for the study of nuclear reactions and the stability of nuclei. Beta decay is also a key process in radiometric dating techniques, such as carbon dating, which rely on the decay of radioactive isotopes to determine the age of archaeological and geological samples.

See Also

• Radioactive decay
• Alpha decay
• Gamma radiation
• Neutrino
• Positron emission tomography