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Radionuclide Dosimetric Data Sheets
Lanthanum-131
Summary data
General
Classification
Isotope: La-131
Atomic number (Z): 57
Mass number (A): 131
Neutron number (N): 74
Radioactive decay
Decay modes: β+, Electron capture
Half-life: 59.0 [m]
Decay constant: 1.9580e-04 [1/s]
Daughters: Ba-131 (100.0%)
Radioactive daughters: Ba-131
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 0.19626 [MeV]
Mean photon energy: 0.66332 [MeV]
Air kerma rate constant, Γ10: 1.842e-17 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 2.736e-17 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 3.144e-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-:
3.144e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 1.063e-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/La-131 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/La-131 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/La-131 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/La-131 Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
1.86002e-05 |
1.368e+01 |
X-ray |
|
4.45292e-03 |
4.314e-02 |
X-ray |
|
4.82366e-03 |
2.547e-02 |
X-ray |
|
3.18187e-02 |
2.255e-01 |
X-ray |
|
3.22056e-02 |
4.152e-01 |
X-ray |
|
3.63167e-02 |
3.968e-02 |
X-ray |
|
3.63920e-02 |
7.689e-02 |
X-ray |
|
3.72607e-02 |
1.633e-02 |
X-ray |
|
1.08081e-01 |
2.500e-01 |
Gamma |
|
1.60687e-01 |
1.802e-02 |
Gamma |
|
2.08509e-01 |
3.025e-02 |
Gamma |
|
2.40593e-01 |
1.375e-02 |
Gamma |
|
2.57087e-01 |
3.427e-02 |
Gamma |
|
2.85246e-01 |
1.240e-01 |
Gamma |
|
3.65162e-01 |
1.693e-01 |
Gamma |
|
4.17783e-01 |
1.795e-01 |
Gamma |
|
4.53659e-01 |
5.875e-02 |
Gamma |
|
5.11000e-01 |
4.620e-01 |
Annihilation photon |
|
5.25851e-01 |
8.725e-02 |
Gamma |
|
5.61785e-01 |
1.100e-02 |
Gamma |
|
5.94080e-01 |
1.438e-02 |
Gamma |
|
8.66138e-01 |
1.047e-02 |
Gamma |
|
5.96535e-01 |
1.189e-02 |
Positron |
|
6.12512e-01 |
5.407e-02 |
Positron |
|
6.84252e-01 |
5.028e-02 |
Positron |
|
7.20071e-01 |
1.899e-02 |
Positron |
|
7.99803e-01 |
3.798e-02 |
Positron |
|
8.48651e-01 |
4.598e-02 |
Positron |
|
1.08630e-05 |
2.919e+00 |
Auger electron |
|
2.91100e-05 |
2.420e-02 |
Auger electron |
|
4.69804e-05 |
1.694e+00 |
Auger electron |
|
4.88180e-05 |
4.630e+00 |
Auger electron |
|
1.14481e-04 |
6.692e-01 |
Auger electron |
|
3.41882e-04 |
1.353e-01 |
Auger electron |
|
5.52265e-04 |
1.512e+00 |
Auger electron |
|
6.90594e-04 |
1.114e-01 |
Auger electron |
|
3.56909e-03 |
5.934e-01 |
Auger electron |
|
4.33558e-03 |
1.896e-01 |
Auger electron |
|
5.13222e-03 |
1.481e-02 |
Auger electron |
|
2.63448e-02 |
5.528e-02 |
Auger electron |
|
3.09583e-02 |
2.550e-02 |
Auger electron |
|
4.24690e-02 |
1.337e-02 |
Conversion electron |
|
7.06320e-02 |
1.741e-01 |
Conversion electron |
|
1.02120e-01 |
2.144e-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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