Nuclide reference
Tc-99 — Technetium-99
The half-life of Tc-99 is 211,100 years. Main decay mode: β⁻ decay to Ru-99 (100%).
Identification
- Element
- Technetium (Tc)
- Atomic number Z
- 43
- Mass number A
- 99
- State
- Radioactive
Key quantities
- Half-life
- 211,100 years
- Specific activity
- 632,900,000 Bq/g
- Gamma constant Γ
- —
- A1 / A2 for transport (SSR-6, НП-053-16)
- 40 TBq / 0.9 TBq
- D-value (НП-067-24)
- 30 TBq
Decay modes
- β⁻ decay → Ru-99 — 100 %
Main gamma lines
| Energy, keV | Yield, % |
|---|---|
| 89.5 | 0.00065 |
Lines of the bare nuclide (ENDF/B-VIII.0), without daughter ingrowth.
Alpha and beta particles
| Radiation | Energy, keV | Yield, % |
|---|---|---|
| β⁻, E max | 293.5 | 100 |
For β⁻ the endpoint (maximum) energy of the spectrum is given. ENDF/B-VIII.0.
Related calculators
Other isotopes of this element
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.