decay constant

decay constant (plural decay constants)

1. In a radioactive material, an atom's probability, per unit time, of decaying; it is related to half-life by the equation ${\displaystyle t_{1/2}={\frac {\ln 2}{\lambda }}}$, where ${\displaystyle t_{1/2}}$ is the half-life, and ${\displaystyle {\lambda }}$ is the decay constant.