Nuclide reference
I-123 — Iodine-123
The half-life of I-123 is 13.223 h. Main decay mode: β⁺ decay / electron capture to Te-123 (100%).
Identification
- Element
- Iodine (I)
- Atomic number Z
- 53
- Mass number A
- 123
- State
- Radioactive
Key quantities
- Half-life
- 13.223 h
- Specific activity
- 7.129e+16 Bq/g
- Gamma constant Γ (H*(10))
- 0.04606 µSv·m²/(MBq·h)
- Dose rate, 1 GBq at 1 m
- ≈ 46.1 µSv/h
- A1 / A2 for transport (SSR-6, НП-053-16)
- 6 TBq / 3 TBq
- D-value (НП-067-24)
- 0.5 TBq
Decay modes
- β⁺ decay / electron capture → Te-123 — 100 %
Main gamma lines
| Energy, keV | Yield, % |
|---|---|
| 158.97 | 83.3 |
| 27.472 · X-ray line | 46.64 |
| 27.202 · X-ray line | 25.05 |
| 528.96 | 1.391 |
| 440.02 | 0.4282 |
| 538.54 | 0.3815 |
| 505.33 | 0.3157 |
| 346.35 | 0.1258 |
| 624.57 | 0.0833 |
| 281.03 | 0.07914 |
Lines of the bare nuclide (ENDF/B-VIII.0), without daughter ingrowth.
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.Dose rate example: point source, no shielding or scatter, Ḣ = Γ·A/r².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.