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Radionuclide Dosimetric Data Sheets
Xenon-129m
Summary data
General
Classification
Isotope: Xe-129m
Atomic number (Z): 54
Mass number (A): 129
Neutron number (N): 75
Radioactive decay
Decay modes: Internal transition
Half-life: 8.88 [d]
Decay constant: 9.0344e-07 [1/s]
Daughters: Xe-129 (100.0%)
Radioactive daughters: None
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 0.18442 [MeV]
Mean photon energy: 0.05172 [MeV]
Air kerma rate constant, Γ10: 7.912e-18 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 7.912e-18 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 2.955e-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-:
2.955e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 8.286e-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/Xe-129m 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/Xe-129m Summary 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/Xe-129m Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
1.66182e-05 |
2.205e+01 |
X-ray |
|
4.09719e-03 |
7.061e-02 |
X-ray |
|
4.41300e-03 |
3.975e-02 |
X-ray |
|
4.70692e-03 |
1.033e-02 |
X-ray |
|
2.94521e-02 |
3.649e-01 |
X-ray |
|
2.97812e-02 |
6.758e-01 |
X-ray |
|
3.35665e-02 |
6.344e-02 |
X-ray |
|
3.36295e-02 |
1.230e-01 |
X-ray |
|
3.43952e-02 |
1.330e-02 |
X-ray |
|
3.44080e-02 |
2.594e-02 |
X-ray |
|
3.95780e-02 |
7.435e-02 |
Gamma |
|
1.96560e-01 |
4.600e-02 |
Gamma |
|
2.61909e-05 |
3.443e+00 |
Auger electron |
|
3.62444e-05 |
1.049e+01 |
Auger electron |
|
1.23600e-04 |
1.298e+00 |
Auger electron |
|
3.24855e-04 |
2.522e-01 |
Auger electron |
|
5.05248e-04 |
2.868e+00 |
Auger electron |
|
6.17658e-04 |
1.642e-01 |
Auger electron |
|
3.32536e-03 |
1.128e+00 |
Auger electron |
|
4.00281e-03 |
3.346e-01 |
Auger electron |
|
4.70738e-03 |
2.542e-02 |
Auger electron |
|
5.02200e-03 |
7.906e-01 |
Conversion electron |
|
2.44715e-02 |
1.026e-01 |
Auger electron |
|
2.86854e-02 |
4.590e-02 |
Auger electron |
|
3.41611e-02 |
9.599e-02 |
Conversion electron |
|
3.86514e-02 |
2.198e-02 |
Conversion electron |
|
1.62004e-01 |
6.350e-01 |
Conversion electron |
|
1.91143e-01 |
1.315e-01 |
Conversion electron |
|
1.91456e-01 |
2.947e-02 |
Conversion electron |
|
1.91785e-01 |
8.771e-02 |
Conversion electron |
|
1.95633e-01 |
5.648e-02 |
Conversion electron |
|
1.96560e-01 |
1.387e-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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