Nuclide reference
Ra-226 — Radium-226
The half-life of Ra-226 is 1,600 years. Main decay mode: α decay to Rn-222 (100%).
Identification
- Element
- Radium (Ra)
- Atomic number Z
- 88
- Mass number A
- 226
- State
- Radioactive
Key quantities
- Half-life
- 1,600 years
- Specific activity
- 3.658e+10 Bq/g
- Gamma constant Γ (H*(10))
- 0.2525 µSv·m²/(MBq·h)
- Dose rate, 1 GBq at 1 m
- ≈ 252 µSv/h
- A1 / A2 for transport (SSR-6, НП-053-16)
- 0.2 TBq / 0.003 TBq
- D-value (НП-067-24)
- 0.04 TBq
Decay modes
- α decay → Rn-222 — 100 %
Main gamma lines
| Energy, keV | Yield, % |
|---|---|
| 609.32 (Bi-214) | 45.49 |
| 351.932 (Pb-214) | 35.59 |
| 295.223 (Pb-214) | 18.42 |
| 1,764.49 (Bi-214) | 15.3 |
| 1,120.29 (Bi-214) | 14.92 |
| 77.109 (Pb-214) · X-ray line | 9.902 |
| 241.995 (Pb-214) | 7.25 |
| 74.817 (Pb-214) · X-ray line | 5.916 |
| 1,238.12 (Bi-214) | 5.834 |
| 186.211 | 3.59 |
Includes daughter nuclides in equilibrium: Rn-222, Po-218, Pb-214, Bi-214, Po-214 (yield per decay of Ra-226); the emitting nuclide is in brackets. Equilibrium is reached in about 27 d. Equilibrium with radon requires a sealed source.
Alpha and beta particles
| Radiation | Energy, keV | Yield, % |
|---|---|---|
| α | 4,784.3 | 94.45 |
| 5,489.5 (Rn-222) | 99.92 | |
| 6,002.3 (Po-218) | 99.98 | |
| 7,686.8 (Po-214) | 99.97 | |
| β⁻, E max | 667.07 (Pb-214) | 45.89 |
| 723.78 (Pb-214) | 40.19 | |
| 3,270 (Bi-214) | 19.1 | |
| 1,540.4 (Bi-214) | 17.57 |
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.Dose rate example: point source, no shielding or scatter, Ḣ = Γ·A/r².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.