Nuclide reference
Ho-166 — Holmium-166
The half-life of Ho-166 is 1.1167 d. Main decay mode: β⁻ decay to Er-166 (100%).
Identification
- Element
- Holmium (Ho)
- Atomic number Z
- 67
- Mass number A
- 166
- State
- Radioactive
Key quantities
- Half-life
- 1.1167 d
- Specific activity
- 2.606e+16 Bq/g
- Gamma constant Γ (H*(10))
- 0.00518 µSv·m²/(MBq·h)
- Dose rate, 1 GBq at 1 m
- ≈ 5.18 µSv/h
- A1 / A2 for transport (SSR-6, НП-053-16)
- 0.4 TBq / 0.4 TBq
- D-value (НП-067-24)
- 2 TBq
Decay modes
- β⁻ decay → Er-166 — 100 %
Main gamma lines
| Energy, keV | Yield, % |
|---|---|
| 80.574 | 6.71 |
| 49.129 · X-ray line | 5.41 |
| 48.223 · X-ray line | 3.049 |
| 1,379.4 | 0.93 |
| 1,581.89 | 0.187 |
| 1,662.48 | 0.12 |
| 1,749.91 | 0.0277 |
| 674 | 0.0194 |
| 705.3 | 0.0131 |
| 785.89 | 0.0119 |
Lines of the bare nuclide (ENDF/B-VIII.0), without daughter ingrowth.
Alpha and beta particles
| Radiation | Energy, keV | Yield, % |
|---|---|---|
| β⁻, E max | 1,854.7 | 50 |
| 1,774.1 | 48.7 | |
| 394.77 | 0.95 | |
| 192.25 | 0.307 |
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.