Nuclide reference
Co-55 — Cobalt-55
The half-life of Co-55 is 17.53 h. Main decay mode: β⁺ decay / electron capture to Fe-55 (100%).
Identification
- Element
- Cobalt (Co)
- Atomic number Z
- 27
- Mass number A
- 55
- State
- Radioactive
Key quantities
- Half-life
- 17.53 h
- Specific activity
- 1.203e+17 Bq/g
- Gamma constant Γ
- —
- A1 / A2 for transport (SSR-6, НП-053-16)
- 0.5 TBq / 0.5 TBq
- D-value (НП-067-24)
- 0.03 TBq
Decay modes
- β⁺ decay / electron capture → Fe-55 — 100 %
Main gamma lines
| Energy, keV | Yield, % |
|---|---|
| 510.999 · annihilation 511 keV | 152.1 |
| 931.1 | 75 |
| 477.2 | 20.18 |
| 1,408.5 | 16.88 |
| 1,316.6 | 7.087 |
| 6.403 · X-ray line | 4.304 |
| 1,370 | 2.918 |
| 6.39 · X-ray line | 2.197 |
| 803.7 | 1.868 |
| 91.9 | 1.163 |
Lines of the bare nuclide (ENDF/B-VIII.0), without daughter ingrowth.
Alpha and beta particles
| Radiation | Energy, keV | Yield, % |
|---|---|---|
| β⁺, E max | 1,498.5 | 46 |
| 1,021.3 | 25.7 | |
| 1,113.2 | 4.3 | |
| 217.6 | 0.0179 |
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.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.