Nuclide reference
Sb-125 — Antimony-125
The half-life of Sb-125 is 2.7586 years. Main decay mode: β⁻ decay to Te-125 (76.91%).
Identification
- Element
- Antimony (Sb)
- Atomic number Z
- 51
- Mass number A
- 125
- State
- Radioactive
Key quantities
- Half-life
- 2.7586 years
- Specific activity
- 3.836e+13 Bq/g
- Gamma constant Γ (H*(10))
- 0.0829 µSv·m²/(MBq·h)
- Dose rate, 1 GBq at 1 m
- ≈ 82.9 µSv/h
- A1 / A2 for transport (SSR-6, НП-053-16)
- 2 TBq / 1 TBq
- D-value (НП-067-24)
- 0.2 TBq
Decay modes
- β⁻ decay → Te-125 — 76.91 %
- β⁻ decay → Te-125m — 23.09 %
Main gamma lines
| Energy, keV | Yield, % |
|---|---|
| 427.874 | 29.6 |
| 27.472 · X-ray line | 24.9 |
| 600.597 | 17.65 |
| 27.472 (Te-125m) · X-ray line | 15.91 |
| 635.95 | 11.22 |
| 463.365 | 10.49 |
| 176.314 | 6.841 |
| 606.713 | 4.982 |
| 35.489 | 4.375 |
| 671.441 | 1.791 |
Includes daughter nuclides in equilibrium: Te-125m (yield per decay of Sb-125); the emitting nuclide is in brackets. Equilibrium is reached in about 1.2 years.
Alpha and beta particles
| Radiation | Energy, keV | Yield, % |
|---|---|---|
| β⁻, E max | 303.34 | 40.3 |
| 130.61 | 17.88 | |
| 621.92 | 13.6 | |
| 95.257 | 13.42 |
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.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.