half_life¶
-
plasmapy.particles.
half_life
(particle: plasmapy.particles.particle_class.Particle, mass_numb: Optional[numbers.Integral] = None) → astropy.units.quantity.Quantity¶ Return the half-life in seconds for unstable isotopes and particles, and
inf
in seconds for stable isotopes and particles.- Parameters
- Returns
half_life_sec – The half-life of the isotope or particle in units of seconds.
- Return type
- 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.
TypeError – The argument is not an
int
orstr
or the mass number is not anint
.
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 aMissingParticleDataError
.Examples
>>> half_life('T') <Quantity 3.888e+08 s> >>> half_life('n') <Quantity 881.5 s> >>> half_life('H-1') <Quantity inf s>