Nuclide reference
I-135 — Iodine-135
The half-life of I-135 is 6.57 h. Main decay mode: β⁻ decay to Xe-135 (83.49%).
Identification
- Element
- Iodine (I)
- Atomic number Z
- 53
- Mass number A
- 135
- State
- Radioactive
Key quantities
- Half-life
- 6.57 h
- Specific activity
- 1.307e+17 Bq/g
- Gamma constant Γ
- —
- A1 / A2 for transport (SSR-6, НП-053-16)
- 0.6 TBq / 0.6 TBq
- D-value (НП-067-24)
- 0.04 TBq
Decay modes
Main gamma lines
| Energy, keV | Yield, % |
|---|---|
| 1,260.41 | 28.7 |
| 1,131.51 | 22.59 |
| 526.561 (Xe-135m) | 13.84 |
| 1,678.03 | 9.557 |
| 1,457.56 | 8.667 |
| 1,038.76 | 7.95 |
| 1,791.2 | 7.72 |
| 546.557 | 7.146 |
| 836.804 | 6.687 |
| 1,706.46 | 4.104 |
Includes daughter nuclides in equilibrium: Xe-135m (yield per decay of I-135); the emitting nuclide is in brackets. Equilibrium is reached in about 1.9 h.
Alpha and beta particles
| Radiation | Energy, keV | Yield, % |
|---|---|---|
| β⁻, E max | 1,366.6 | 23.6 |
| 948.94 | 21.8 | |
| 835.79 | 8.8 | |
| 658.68 | 8 |
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.