half_life

plasmapy.particles.atomic.half_life(particle: Particle, mass_numb: Integral | None = None) → Quantity

Return the half-life in seconds for unstable isotopes and particles, and inf seconds for stable isotopes and particles.

Parameters:

• particle (particle-like) – A string representing an isotope or particle, an integer representing an atomic number, or an instance of the Particle class.

• mass_numb (integer, optional) – The mass number of an isotope.

Returns:

The half-life of the isotope or particle in units of seconds.

Return type:

Quantity

Raises:

• InvalidParticleError – If the argument does not correspond to a valid particle or contradictory information is provided.

• MissingParticleDataError – If no half-life data is available for the isotope.

Notes

Accurate half-life data is not known for all isotopes. Some isotopes may have upper or lower limits on the half-life, in which case this function will return a string with that information and issue a MissingParticleDataError. When no isotope information is available, then this function raises a MissingParticleDataError.

Examples

>>> half_life("T")
<Quantity 3.888e+08 s>
>>> half_life("n")
<Quantity 881.5 s>
>>> half_life("H-1")
<Quantity inf s>