Nuclide reference
W-178 — Tungsten-178
The half-life of W-178 is 21.6 d. Main decay mode: electron capture to Ta-178 (100%).
Identification
- Element
- Tungsten (W)
- Atomic number Z
- 74
- Mass number A
- 178
- State
- Radioactive
Key quantities
- Half-life
- 21.6 d
- Specific activity
- 1.257e+15 Bq/g
- Gamma constant Γ
- —
- A1 / A2 for transport (SSR-6, НП-053-16)
- 9 TBq / 5 TBq
- D-value (НП-067-24)
- 0.9 TBq
Decay modes
- electron capture → Ta-178 — 100 %
Main gamma lines
| Energy, keV | Yield, % |
|---|---|
| 55.784 (Ta-178) · X-ray line | 42.7 |
| 54.606 (Ta-178) · X-ray line | 24.4 |
| 93.13 (Ta-178) | 6.578 |
| 510.999 (Ta-178) · annihilation 511 keV | 2.481 |
| 1,350.55 (Ta-178) | 1.176 |
| 1,340.85 (Ta-178) | 1.028 |
| 1,106.09 (Ta-178) | 0.5358 |
| 1,402.87 (Ta-178) | 0.4801 |
| 1,496.01 (Ta-178) | 0.2689 |
| 1,183.38 (Ta-178) | 0.1695 |
Includes daughter nuclides in equilibrium: Ta-178 (yield per decay of W-178); the emitting nuclide is in brackets. Equilibrium is reached in about 1.1 h.
Alpha and beta particles
| Radiation | Energy, keV | Yield, % |
|---|---|---|
| β⁺, E max | 915 (Ta-178) | 0.9003 |
| 821.86 (Ta-178) | 0.3401 |
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.