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Radionuclide Dosimetric Data Sheets
Iodine-120
Summary data
General
Classification
Isotope: I-120
Atomic number (Z): 53
Mass number (A): 120
Neutron number (N): 67
Radioactive decay
Decay modes: β+, Electron capture
Half-life: 81.6 [m]
Decay constant: 1.4157e-04 [1/s]
Daughters: Te-120 (100.0%)
Radioactive daughters: None
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 1.168 [MeV]
Mean photon energy: 2.66108 [MeV]
Air kerma rate constant, Γ10: 6.375e-17 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 9.016e-17 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 1.871e-13 [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-:
1.871e-13 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 4.264e-13
[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-120 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-120 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-120 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-120 Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
1.36107e-05 |
4.147e+00 |
X-ray |
|
3.75695e-03 |
1.096e-02 |
X-ray |
|
2.71868e-02 |
6.988e-02 |
X-ray |
|
2.74652e-02 |
1.301e-01 |
X-ray |
|
3.09378e-02 |
1.198e-02 |
X-ray |
|
3.09901e-02 |
2.323e-02 |
X-ray |
|
5.11000e-01 |
1.364e+00 |
Annihilation photon |
|
5.60400e-01 |
6.960e-01 |
Gamma |
|
6.01100e-01 |
5.512e-02 |
Gamma |
|
6.41100e-01 |
8.422e-02 |
Gamma |
|
6.62100e-01 |
1.051e-02 |
Gamma |
|
9.75100e-01 |
1.496e-02 |
Gamma |
|
1.20160e+00 |
2.506e-02 |
Gamma |
|
1.40420e+00 |
1.670e-02 |
Gamma |
|
1.41090e+00 |
1.253e-02 |
Gamma |
|
1.52300e+00 |
1.086e-01 |
Gamma |
|
1.53490e+00 |
1.810e-02 |
Gamma |
|
1.54300e+00 |
1.114e-02 |
Gamma |
|
1.79000e+00 |
1.253e-02 |
Gamma |
|
2.18800e+00 |
1.441e-02 |
Gamma |
|
2.40400e+00 |
1.058e-02 |
Gamma |
|
2.45480e+00 |
1.949e-02 |
Gamma |
|
2.49180e+00 |
1.162e-02 |
Gamma |
|
2.56440e+00 |
2.506e-02 |
Gamma |
|
3.04700e+00 |
1.253e-02 |
Gamma |
|
9.60166e-01 |
2.124e-02 |
Positron |
|
1.13128e+00 |
6.183e-02 |
Positron |
|
1.38593e+00 |
1.925e-02 |
Positron |
|
1.54217e+00 |
2.692e-02 |
Positron |
|
1.56134e+00 |
1.137e-02 |
Positron |
|
1.84472e+00 |
2.922e-01 |
Positron |
|
2.09928e+00 |
1.895e-01 |
Positron |
|
2.29235e-05 |
2.026e+00 |
Auger electron |
|
2.49263e-05 |
6.767e-01 |
Auger electron |
|
1.21028e-04 |
2.331e-01 |
Auger electron |
|
2.95373e-04 |
4.313e-02 |
Auger electron |
|
4.49478e-04 |
5.216e-01 |
Auger electron |
|
5.41143e-04 |
2.010e-02 |
Auger electron |
|
3.08439e-03 |
2.049e-01 |
Auger electron |
|
3.67846e-03 |
5.801e-02 |
Auger electron |
|
2.26653e-02 |
2.259e-02 |
Auger 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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