Nuclide reference
Ac-228 — Actinium-228
The half-life of Ac-228 is 6.15 h. Main decay mode: β⁻ decay to Th-228 (100%).
Identification
- Element
- Actinium (Ac)
- Atomic number Z
- 89
- Mass number A
- 228
- State
- Radioactive
Key quantities
- Half-life
- 6.15 h
- Specific activity
- 8.269e+16 Bq/g
- Gamma constant Γ
- —
- A1 / A2 for transport (SSR-6, НП-053-16)
- 0.6 TBq / 0.5 TBq
- D-value (НП-067-24)
- 0.03 TBq
Decay modes
- β⁻ decay → Th-228 — 100 %
Main gamma lines
| Energy, keV | Yield, % |
|---|---|
| 911.196 | 26.2 |
| 16.132 · X-ray line | 18.48 |
| 12.9603 · X-ray line | 16.12 |
| 968.96 | 15.9 |
| 338.32 | 11.4 |
| 964.786 | 4.99 |
| 463.002 | 4.45 |
| 794.942 | 4.31 |
| 209.248 | 3.97 |
| 270.245 | 3.55 |
Lines of the bare nuclide (ENDF/B-VIII.0), without daughter ingrowth.
Alpha and beta particles
| Radiation | Energy, keV | Yield, % |
|---|---|---|
| β⁻, E max | 1,154.8 | 31 |
| 1,727.7 | 12.4 | |
| 535.47 | 8.8 | |
| 1,000.8 | 6.67 |
For β⁻ the endpoint (maximum) energy of the spectrum is given. ENDF/B-VIII.0.
Related calculators
Other isotopes of this element
Reference data vs computed valuesHalf-life, gamma lines and D-value are reference data (ENDF/B-VIII.0, НП-067-24).Gamma constant Γ is H*(10) at 1 m computed from ICRP-107 spectra (NIST µ_en/ρ, ICRP-74 Table A.21) including short-lived progeny in equilibrium (e.g. Cs-137/Ba-137m, Ra-226 series); specific activity uses molar mass M ≈ mass number A.K-series X-ray energies are from NIST SRD 128 (Deslattes et al., 2003): in ENDF/B-VIII.0 they are given to 1 % and shifted by up to 0.7 keV for heavy elements. L-series lines and all yields are ENDF/B-VIII.0.