Actinide Alpha Decay Chains
| Actinides | Half-life | Fission products | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Cm | Puƒ | Cf | Ac№ | 10–22 y | m is meta |
Kr | Cd₡ | |||
| Uƒ | Pu | Cmƒ | 29–90 y | Cs | Sr | Sm₡ | Sn | |||
| ƒ for fissile |
Cfƒ | Amƒ | Cfƒ | 140 y – 1.6 ky |
No fission products |
|||||
| Am | Ra№ | Bk | ||||||||
| Pu | Th | Cm | Am | 5–7 ky | ||||||
| 4n | Cmƒ | Cm | Puƒ | 8–24 ky | ||||||
| Npƒ | Uƒ | Th№ | Pa№ | 32–160 ky | ||||||
| Cm | 4n+1 | U№ | 211–348 ky | Tc | ₡ can capture | Sn | Se | |||
| U | Np | Pu | Cmƒ | 0.37–23 My | Cs₡ | Zr | Pd | I | ||
| Pu | № for NORM |
4n+2 | 4n+3 | 80 My | 6-7% | 4-5% | 1.25% | 0.1-1% | <0.05% | |
| Th№ | U№ | Uƒ№ | 0.7–14 Gy | fission product yield | ||||||
In the four tables below, the minor branches of decay (with the branching ratio of less than 0.0001%) are omitted. The energy release includes the total kinetic energy of all the emitted particles (electrons, alpha particles, gamma quanta, neutrinos, Auger electrons and X-rays) and the recoil nucleus, assuming that the original nucleus was at rest. The letter 'a' represents a year.
In the tables below (except neptunium), the historic names of the naturally occurring nuclides are also given. These names were used at the time when the decay chains were first discovered and investigated. From these historical names one can locate the particular chain to which the nuclide belongs, and replace it with its modern name.
The three naturally-occurring actinide alpha decay chains given below—thorium, uranium/radium (from U-238), and actinium (from U-235)—each ends with its own specific lead isotope (Pb-208, Pb-206, and Pb-207 respectively). All these isotopes are stable and are also present in nature as primordial nuclides, but their excess amounts in comparison with lead-204 (which has only a primordial origin) can be used in the technique of uranium-lead dating to date rocks.
Read more about this topic: Radium Series
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