Nuclide reference
Pb-212 — Lead-212
The half-life of Pb-212 is 10.64 h. Main decay mode: β⁻ decay to Bi-212 (100%).
Identification
- Element
- Lead (Pb)
- Atomic number Z
- 82
- Mass number A
- 212
- State
- Radioactive
Key quantities
- Half-life
- 10.64 h
- Specific activity
- 5.14e+16 Bq/g
- Gamma constant Γ
- —
- A1 / A2 for transport (SSR-6, НП-053-16)
- 0.7 TBq / 0.2 TBq
- D-value (НП-067-24)
- 0.05 TBq
Decay modes
- β⁻ decay → Bi-212 — 100 %
Main gamma lines
| Energy, keV | Yield, % |
|---|---|
| 238.632 | 43.6 |
| 2,614.51 (Tl-208) | 39.8 |
| 583.187 (Tl-208) | 33.91 |
| 77.109 · X-ray line | 16.84 |
| 74.817 · X-ray line | 10.06 |
| 510.77 (Tl-208) | 9.017 |
| 727.33 (Bi-212) | 7.367 |
| 860.557 (Tl-208) | 4.987 |
| 300.087 | 3.301 |
| 277.371 (Tl-208) | 2.633 |
Includes daughter nuclides in equilibrium: Bi-212, Po-212, Tl-208 (yield per decay of Pb-212); the emitting nuclide is in brackets. Equilibrium is reached in about 7.8 h. In transient equilibrium a daughter's activity exceeds the parent's, so a yield can be above 100%.
Alpha and beta particles
| Radiation | Energy, keV | Yield, % |
|---|---|---|
| α | 6,050.8 (Bi-212) | 27.76 |
| 6,089.9 (Bi-212) | 10.77 | |
| 5,768 (Bi-212) | 0.675 | |
| 8,784.9 (Po-212) | 70.77 | |
| β⁻, E max | 331.27 | 83.1 |
| 569.9 | 11.9 | |
| 2,252.1 (Bi-212) | 61.17 | |
| 1,801.3 (Tl-208) | 19.59 |
For β⁻ the endpoint (maximum) energy of the spectrum is given. ENDF/B-VIII.0.
Related calculators
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.