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Nuclide reference

I-122 — Iodine-122

The half-life of I-122 is 3.63 min. Main decay mode: β⁺ decay / electron capture to Te-122 (100%).

Identification

Element
Iodine (I)
Atomic number Z
53
Mass number A
122
State
Radioactive

Key quantities

Half-life
3.63 min
Specific activity
1.571e+19 Bq/g
Gamma constant Γ
—
D-value (НП-067-24)
—

Decay modes

  • β⁺ decay / electron capture → Te-122 — 100 %

Main gamma lines

Energy, keVYield, %
510.999 · annihilation 511 keV156.3
564.11918
27.472 · X-ray line8.829
27.202 · X-ray line4.743
692.7941.355
793.2781.327
683.6470.7956
1,746.930.333
1,256.90.2808
2,192.290.2664

Lines of the bare nuclide (ENDF/B-VIII.0), without daughter ingrowth.

Alpha and beta particles

RadiationEnergy, keVYield, %
β⁺, E max3,21267
2,647.910
1,854.60.6
1,955.10.31

For β⁺ the endpoint (maximum) energy of the spectrum is given. ENDF/B-VIII.0.

Related calculators

DecayActivity ↔ massDose rate

Other isotopes of this element

I-123I-124I-125I-129I-131
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.

Iodine-122 (I-122) — reference data

What is in the card

This card gathers the key data of radionuclide I-122 in one place: half-life, decay modes, main gamma lines, alpha and beta particle energies, gamma constant, specific activity and the D-value for source categorization. Decay and emission data are from ENDF/B-VIII.0; the D-value follows NP-067-24; the gamma constant is the ambient dose equivalent H*(10) at 1 m, computed from ICRP-107 spectra.

How to use the data

Half-life and specific activity let you recalculate the activity of a I-122 source to the delivery or disposal date — use the decay calculator. Gamma lines with yields identify the nuclide from a spectrum and pick the line for gamma spectrometry; the gamma constant Γ gives the dose rate at a distance, while the D-value and A1/A2 set the source category and the package type for transport.