Nuclide reference
Tb-158 — Terbium-158
The half-life of Tb-158 is 180 years. Main decay mode: β⁺ decay / electron capture to Gd-158 (83.4%).
Identification
- Element
- Terbium (Tb)
- Atomic number Z
- 65
- Mass number A
- 158
- State
- Radioactive
Key quantities
- Half-life
- 180 years
- Specific activity
- 4.651e+11 Bq/g
- Gamma constant Γ
- —
- A1 / A2 for transport (SSR-6, НП-053-16)
- 1 TBq / 1 TBq
- D-value (НП-067-24)
- 0.09 TBq
Decay modes
- β⁺ decay / electron capture → Gd-158 — 83.4 %
- β⁻ decay → Dy-158 — 16.6 %
Main gamma lines
| Energy, keV | Yield, % |
|---|---|
| 944.189 | 43.87 |
| 42.997 · X-ray line | 41.62 |
| 42.31 · X-ray line | 22.81 |
| 962.126 | 20.27 |
| 79.513 | 11.63 |
| 181.944 | 9.914 |
| 780.183 | 9.563 |
| 98.918 | 4.295 |
| 1,107.63 | 2.145 |
| 1,187.14 | 1.685 |
Lines of the bare nuclide (ENDF/B-VIII.0), without daughter ingrowth.
Alpha and beta particles
| Radiation | Energy, keV | Yield, % |
|---|---|---|
| β⁻, E max | 836.08 | 15.49 |
| 617.86 | 1.099 |
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.