Nuclide reference
Cs-136 — Caesium-136
The half-life of Cs-136 is 13.16 d. Main decay mode: β⁻ decay to Ba-136 (88.93%).
Identification
- Element
- Caesium (Cs)
- Atomic number Z
- 55
- Mass number A
- 136
- State
- Radioactive
Key quantities
- Half-life
- 13.16 d
- Specific activity
- 2.699e+15 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 → Ba-136 — 88.93 %
- β⁻ decay → Ba-136m — 11.07 %
Main gamma lines
| Energy, keV | Yield, % |
|---|---|
| 818.514 | 88.74 |
| 1,048.07 | 68.8 |
| 340.547 | 42.17 |
| 1,235.36 | 20.04 |
| 273.646 | 11.07 |
| 1,048.07 (Ba-136m) | 11.05 |
| 818.514 (Ba-136m) | 11.03 |
| 176.602 | 9.97 |
| 153.246 | 5.753 |
| 86.36 | 5.185 |
Includes daughter nuclides in equilibrium: Ba-136m (yield per decay of Cs-136); the emitting nuclide is in brackets. Equilibrium is reached in about 2.2 s.
Alpha and beta particles
| Radiation | Energy, keV | Yield, % |
|---|---|---|
| β⁻, E max | 341.07 | 70.3 |
| 681.6 | 13 | |
| 407.97 | 10.5 | |
| 494.32 | 4.7 |
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.