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Radionuclide Dosimetric Data Sheets
Iodine-129
Summary data
General
Classification
Isotope: I-129
Atomic number (Z): 53
Mass number (A): 129
Neutron number (N): 76
Radioactive decay
Decay modes: β-
Half-life: 15700000.0 [y]
Decay constant: 1.3990e-15 [1/s]
Daughters: Xe-129 (100.0%)
Radioactive daughters: None
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 0.06507 [MeV]
Mean photon energy: 0.02517 [MeV]
Air kerma rate constant, Γ10: 4.378e-18 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 4.378e-18 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 1.043e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for alphas, Δα: 0.000e+00
[Gy·kg/Bq·s]
Equilibrium dose constant for betas/electrons, Δβ-,β+,e-:
1.043e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 4.033e-15
[Gy·kg/Bq·s]
Dose point kernels (plot)
Dose point kernel source: Graves, et al. Medical Physics. 2019 Nov.; 46(11):5284-5293.
Note: Bins are spaced every 0.1 mm until a radius of 10 cm, and every 1 mm until a radius of 2 m.
Download tabulated dose point kernel file here: www.mirdsoft.org/products/MIRDspecs/I-129 DPK.csv
Summary spectra (plot)
Spectra source: ICRP Publication 107: Nuclear Decay Data for Dosimetric Calculations. Ann. ICRP 2008, 38 (3).
Download tabulated summary spectra file here: www.mirdsoft.org/products/MIRDspecs/I-129 Summary Spectrum.csv
Beta spectra (plot)
Spectra source: ICRP Publication 107: Nuclear Decay Data for Dosimetric Calculations. Ann. ICRP 2008, 38 (3).
Download tabulated beta spectra file here: www.mirdsoft.org/products/MIRDspecs/I-129 Beta Spectrum.csv
Tabulated data
Summary spectra (table)
Spectra source: ICRP Publication 107: Nuclear Decay Data for Dosimetric Calculations. Ann. ICRP 2008, 38 (3).
Note: Radiations with yield < 0.01 are excluded from the table, but are available in the linked *.csv data.
Download tabulated summary spectra file here: www.mirdsoft.org/products/MIRDspecs/I-129 Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
1.66175e-05 |
1.106e+01 |
X-ray |
|
4.09719e-03 |
3.552e-02 |
X-ray |
|
4.41300e-03 |
2.086e-02 |
X-ray |
|
2.94521e-02 |
2.044e-01 |
X-ray |
|
2.97812e-02 |
3.786e-01 |
X-ray |
|
3.35665e-02 |
3.554e-02 |
X-ray |
|
3.36295e-02 |
6.890e-02 |
X-ray |
|
3.44080e-02 |
1.453e-02 |
X-ray |
|
3.95780e-02 |
7.510e-02 |
Gamma |
|
5.02689e-02 |
1.000e+00 |
Beta |
|
2.61607e-05 |
1.722e+00 |
Auger electron |
|
3.62385e-05 |
5.261e+00 |
Auger electron |
|
1.23783e-04 |
6.466e-01 |
Auger electron |
|
3.19360e-04 |
1.218e-01 |
Auger electron |
|
5.05066e-04 |
1.444e+00 |
Auger electron |
|
6.17165e-04 |
8.260e-02 |
Auger electron |
|
3.32456e-03 |
5.694e-01 |
Auger electron |
|
4.00169e-03 |
1.689e-01 |
Auger electron |
|
4.70571e-03 |
1.283e-02 |
Auger electron |
|
5.02200e-03 |
7.986e-01 |
Conversion electron |
|
2.44715e-02 |
5.747e-02 |
Auger electron |
|
2.86854e-02 |
2.571e-02 |
Auger electron |
|
3.41611e-02 |
9.696e-02 |
Conversion electron |
|
3.86514e-02 |
2.220e-02 |
Conversion electron |
Useful Links
Isotope decay characteristics are periodically updated as better measurements can be made - changes that may not be reflected on this page. Please see useful links:
National Nuclear Data Center (NNDC): https://www.nndc.bnl.gov/nudat3/mird/
International Atomic Energy Agency (IAEA) Livechart: https://www-nds.iaea.org/relnsd/vcharthtml/VChartHTML.html
Reference Links
ICRP Report 107: https://www.icrp.org/publication.asp?id=ICRP%20Publication%20107
Graves et al. Dose Point Kernels: https://doi.org/10.1002/mp.13789
MIRD Decay Schemes 2nd Edition: https://sites.snmmi.org/SNMMI-MAIN/iCore/Store/StoreLayouts/Item_Detail.aspx?iProductCode=0-932004-80-6
MIRDsoft MIRDspecs version 20250101 (www.mirdsoft.org)
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