Half-Life vs Electron Volts: Why Do Helium Isotopes Use Different Measurements?

Click For Summary
SUMMARY

The discussion clarifies the relationship between half-life measurements and electron volts (eV) in the context of helium isotopes. Helium-6, Helium-7, Helium-8, Helium-9, and Helium-10 exhibit varying decay modes, with some isotopes transitioning through neutron emission, which occurs on femtosecond timescales. The energy values in electron volts are derived from the uncertainty principle, specifically the equation "Energy * time < h-bar," where 'h-bar' represents Planck's constant. This relationship allows for the calculation of decay times from energy values.

PREREQUISITES
  • Understanding of nuclear decay processes
  • Familiarity with isotopes and their half-lives
  • Knowledge of the uncertainty principle in quantum mechanics
  • Basic grasp of energy units, specifically electron volts (eV)
NEXT STEPS
  • Study the uncertainty principle in quantum mechanics
  • Learn about neutron emission and its implications in nuclear physics
  • Explore the concept of half-life in various isotopes
  • Investigate the conversion between energy units and decay times
USEFUL FOR

Students and professionals in nuclear physics, researchers studying isotopic behavior, and anyone interested in the principles of quantum mechanics and energy measurements.

Nim
Messages
74
Reaction score
0
I was looking at a http://chemlab.pc.maricopa.edu/periodic/isotopes.html and was wondering why the half-life was sometimes replaced with electron volts? There's an example from the table below:

Code: 
Helium-6    806.7 milliseconds   -> Lithium-6
Helium-7    160 KEV              -> Helium-6
Helium-8    119.0 milliseconds   -> Lithium-8
Helium-9    0.3 MeV              -> Helium-8
Helium-10   0.3 MeV              -> Helium-9
 
Last edited by a moderator:
Physics news on Phys.org
In the examples you've shown, the ones denoted by an energy decay rapidly via neutron emission. This happens on timescales on the order of femtoseconds or less. The value for the energy comes out of the uncertainty relationship. Effectively "Energy * time < h-bar", where 'h-bar' is Planck's constant. If you solve the equation for time using the energy value given and Planck's constant, you get a value for the time of the decay.

Sorry for not being able to use all these cool board features to make it a nicer presentation.