Nuclide reference
Te-129m — Tellurium-129m
The half-life of Te-129m is 33.6 d. Main decay mode: isomeric transition to Te-129 (63%).
Identification
- Element
- Tellurium (Te)
- Atomic number Z
- 52
- Mass number A
- 129
- State
- Radioactive
Key quantities
- Half-life
- 33.6 d
- Specific activity
- 1.115e+15 Bq/g
- Gamma constant Γ
- —
- A1 / A2 for transport (SSR-6, НП-053-16)
- 0.8 TBq / 0.4 TBq
- D-value (НП-067-24)
- 1 TBq
Decay modes
Main gamma lines
| Energy, keV | Yield, % |
|---|---|
| 27.472 · X-ray line | 15.01 |
| 27.81 (Te-129) | 10.3 |
| 27.202 · X-ray line | 8.017 |
| 459.6 (Te-129) | 4.858 |
| 695.88 | 3.071 |
| 487.39 (Te-129) | 0.8939 |
| 729.57 | 0.7167 |
| 278.43 (Te-129) | 0.3575 |
| 1,083.85 (Te-129) | 0.3109 |
| 250.62 (Te-129) | 0.2414 |
Includes daughter nuclides in equilibrium: Te-129 (yield per decay of Te-129m); the emitting nuclide is in brackets. Equilibrium is reached in about 8.1 h.
Alpha and beta particles
| Radiation | Energy, keV | Yield, % |
|---|---|---|
| β⁻, E max | 1,608.5 | 33.09 |
| 912.61 | 3.117 | |
| 1,475.2 (Te-129) | 56.15 | |
| 1,015.7 (Te-129) | 5.867 |
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.