Nuclide reference
La-137 — Lanthanum-137
The half-life of La-137 is 60,000 years. Main decay mode: electron capture to Ba-137 (100%).
Identification
- Element
- Lanthanum (La)
- Atomic number Z
- 57
- Mass number A
- 137
- State
- Radioactive
Key quantities
- Half-life
- 60,000 years
- Specific activity
- 1.609e+9 Bq/g
- Gamma constant Γ
- —
- A1 / A2 for transport (SSR-6, НП-053-16)
- 30 TBq / 6 TBq
- D-value (НП-067-24)
- 20 TBq
Decay modes
- electron capture → Ba-137 — 100 %
Main gamma lines
| Energy, keV | Yield, % |
|---|---|
| 32.193 · X-ray line | 40.32 |
| 31.817 · X-ray line | 21.9 |
| 36.378 · X-ray line | 7.467 |
| 4.45131 · X-ray line | 5.126 |
| 4.89459 · X-ray line | 4.773 |
| 36.304 · X-ray line | 3.854 |
| 37.249 · X-ray line | 1.586 |
| 37.249 · X-ray line | 0.8141 |
| 5.62765 · X-ray line | 0.7721 |
| 3.99847 · X-ray line | 0.6155 |
Lines of the bare nuclide (ENDF/B-VIII.0), without daughter ingrowth.
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.