Nuclide reference
Ra-228 — Radium-228
The half-life of Ra-228 is 5.75 years. Main decay mode: β⁻ decay to Ac-228 (100%).
Identification
- Element
- Radium (Ra)
- Atomic number Z
- 88
- Mass number A
- 228
- State
- Radioactive
Key quantities
- Half-life
- 5.75 years
- Specific activity
- 1.009e+13 Bq/g
- Gamma constant Γ
- —
- A1 / A2 for transport (SSR-6, НП-053-16)
- 0.6 TBq / 0.02 TBq
- D-value (НП-067-24)
- 0.03 TBq
Decay modes
- β⁻ decay → Ac-228 — 100 %
Main gamma lines
| Energy, keV | Yield, % |
|---|---|
| 911.196 (Ac-228) | 26.2 |
| 16.132 (Ac-228) · X-ray line | 18.48 |
| 12.9603 (Ac-228) · X-ray line | 16.12 |
| 968.96 (Ac-228) | 15.9 |
| 338.32 (Ac-228) | 11.4 |
| 964.786 (Ac-228) | 4.991 |
| 463.002 (Ac-228) | 4.451 |
| 794.942 (Ac-228) | 4.311 |
| 209.248 (Ac-228) | 3.97 |
| 13.52 | 1.603 |
Includes daughter nuclides in equilibrium: Ac-228 (yield per decay of Ra-228); the emitting nuclide is in brackets. Equilibrium is reached in about 43 h.
Alpha and beta particles
| Radiation | Energy, keV | Yield, % |
|---|---|---|
| β⁻, E max | 39.13 | 40 |
| 12.73 | 30 | |
| 25.61 | 20 | |
| 1,154.8 (Ac-228) | 31 |
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.