Aluminium-26
Aluminium-26 (26Al, Al-26) is a radioactive isotope of the chemical element aluminium, decaying by either positron emission or electron capture to stable magnesium-26. The half-life of 26Al is 717,000 years. This is far too short for the isotope to survive as a primordial nuclide, but a small amount of it is produced by collisions of atoms with cosmic ray protons.
| General | |
|---|---|
| Symbol | 26Al |
| Names | aluminium-26, 26Al, Al-26 |
| Protons (Z) | 13 |
| Neutrons (N) | 13 |
| Nuclide data | |
| Natural abundance | trace (cosmogenic) |
| Half-life (t1/2) | 7.17×105 years |
| Spin | 5+ |
| Decay modes | |
| Decay mode | Decay energy (MeV) |
| β+ | 4.00414 |
| ε | 4.00414 |
| Isotopes of aluminium Complete table of nuclides | |
Decay of aluminium-26 also produces gamma rays and x-rays. The x-rays and Auger electrons are emitted by the excited atomic shell of the daughter 26Mg after the electron capture which typically leaves a hole in one of the lower sub-shells.
Because it is radioactive, it is typically stored behind at least 5 centimetres (2 in) of lead. Contact with 26Al may result in radiological contamination. This necessitates special tools for transfer, use, and storage.