Beta Decay

Convertible Layer

Table of Contents

Beta decay is the most common type of radioactive decay, observed in over 97% of all known unstable nuclides.

It is where a nucleus transforms by emitting a beta particle (an electron or anti-electron) and an antineutrino or neutrino.

There are 3 Types of Beta Decay.

A neutron converts into a proton, emitting an electron and an electron-antineutrino. The atomic number increases by 1, mass number unchanged.

A proton converts into a neutron, emitting an anti-electron and an electron-neutrino. The atomic number decreases by 1.

A proton-rich nucleus absorbs an inner-shell electron, which combines with a proton to form a neutron and emit a neutrino.

Examples

Type	Parent Isotope	Decay Equation	Daughter Isotope	Half-life
β⁻	Carbon-14	$^{14}_{6}C \rightarrow ^{14}_{7}N + e^- + \bar{\nu}_e$	Nitrogen-14	5,730 years
β⁻	Strontium-90	$^{90}_{38}Sr \rightarrow ^{90}_{39}Y + e^- + \bar{\nu}_e$	Yttrium-90	29 years
β⁺	Carbon-11	$^{11}_{6}C \rightarrow ^{11}_{5}B + e^+ + \nu_e$	Boron-11	20 minutes
β⁺	Fluorine-18	$^{18}_{9}F \rightarrow ^{18}_{8}O + e^+ + \nu_e$	Oxygen-18	110 minutes
Electron capture	Potassium-40	$^{40}_{19}K + e^- \rightarrow ^{40}_{18}Ar + \nu_e$	Argon-40	1.25 billion years

Radiocarbon dating – Carbon-14 beta decay measures the age of organic artifacts.
PET scans – Positron-emitting isotopes like Fluorine-18 annihilate with electrons, producing gamma rays for medical imaging.
Nuclear reactors – Beta decay of fission products produces delayed neutrons essential for reactor control.
Betavoltaic batteries – Beta particles generate electricity in long-lasting pacemaker batteries.