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Radionuclide Dosimetric Data Sheets
Thorium-229
Summary data
General
Classification
Isotope: Th-229
Atomic number (Z): 90
Mass number (A): 229
Neutron number (N): 139
Radioactive decay
Decay modes: α
Half-life: 7340.0 [y]
Decay constant: 2.9925e-12 [1/s]
Daughters: Ra-225 (100.0%)
Radioactive daughters: Ra-225
Dosimetric constants
Mean alpha energy: 4.9576 [MeV]
Mean electron energy: 0.12174 [MeV]
Mean photon energy: 0.09705 [MeV]
Air kerma rate constant, Γ10: 2.728e-17 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 2.728e-17 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 8.138e-13 [Gy·kg/Bq·s]
Equilibrium dose constant for alphas, Δα: 7.943e-13
[Gy·kg/Bq·s]
Equilibrium dose constant for betas/electrons, Δβ-,β+,e-:
1.950e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 1.555e-14
[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/Th-229 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/Th-229 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/Th-229 Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
7.12154e-05 |
2.946e+01 |
X-ray |
|
2.89190e-03 |
1.451e-01 |
X-ray |
|
1.06609e-02 |
2.026e-02 |
X-ray |
|
1.21973e-02 |
3.448e-02 |
X-ray |
|
1.23447e-02 |
3.032e-01 |
X-ray |
|
1.47500e-02 |
1.975e-02 |
X-ray |
|
1.48529e-02 |
6.159e-02 |
X-ray |
|
1.53013e-02 |
2.288e-01 |
X-ray |
|
1.53805e-02 |
1.039e-02 |
X-ray |
|
1.54583e-02 |
1.897e-02 |
X-ray |
|
1.79232e-02 |
4.982e-02 |
X-ray |
|
3.15000e-02 |
1.190e-02 |
Gamma |
|
8.57602e-02 |
1.534e-01 |
X-ray |
|
8.62500e-02 |
1.334e-02 |
Gamma |
|
8.64000e-02 |
2.565e-02 |
Gamma |
|
8.88641e-02 |
2.506e-01 |
X-ray |
|
9.98380e-02 |
2.854e-02 |
X-ray |
|
1.00546e-01 |
5.554e-02 |
X-ray |
|
1.03453e-01 |
1.401e-02 |
X-ray |
|
1.36990e-01 |
1.180e-02 |
Gamma |
|
1.56409e-01 |
1.190e-02 |
Gamma |
|
1.93509e-01 |
4.412e-02 |
Gamma |
|
2.10853e-01 |
2.770e-02 |
Gamma |
|
2.56552e-05 |
8.162e+00 |
Auger electron |
|
1.22108e-04 |
8.153e+00 |
Auger electron |
|
1.35655e-04 |
3.613e-02 |
Auger electron |
|
1.82497e-04 |
4.619e+00 |
Auger electron |
|
4.95321e-04 |
1.408e+00 |
Auger electron |
|
1.33577e-03 |
3.972e-01 |
Auger electron |
|
2.22559e-03 |
2.508e+00 |
Auger electron |
|
2.60487e-03 |
4.059e-01 |
Auger electron |
|
2.78801e-03 |
8.322e-02 |
Conversion electron |
|
3.13867e-03 |
2.287e-02 |
Auger electron |
|
6.83000e-03 |
2.176e-01 |
Conversion electron |
|
7.32630e-03 |
6.082e-02 |
Conversion electron |
|
9.37258e-03 |
6.040e-01 |
Auger electron |
|
9.93400e-03 |
2.267e-01 |
Conversion electron |
|
1.10680e-02 |
6.230e-02 |
Conversion electron |
|
1.11000e-02 |
2.111e-02 |
Conversion electron |
|
1.23034e-02 |
2.927e-01 |
Auger electron |
|
1.23380e-02 |
4.518e-02 |
Conversion electron |
|
1.35863e-02 |
1.943e-01 |
Conversion electron |
|
1.52691e-02 |
3.361e-02 |
Auger electron |
|
1.73600e-02 |
6.723e-02 |
Conversion electron |
|
1.92400e-02 |
1.269e-02 |
Conversion electron |
|
2.02300e-02 |
4.960e-02 |
Conversion electron |
|
2.03300e-02 |
5.318e-02 |
Conversion electron |
|
2.16163e-02 |
1.208e-01 |
Conversion electron |
|
2.23440e-02 |
1.229e-02 |
Conversion electron |
|
2.35880e-02 |
4.192e-02 |
Conversion electron |
|
2.42600e-02 |
2.962e-02 |
Conversion electron |
|
2.53900e-02 |
4.053e-02 |
Conversion electron |
|
2.65263e-02 |
1.658e-02 |
Conversion electron |
|
2.73640e-02 |
2.421e-02 |
Conversion electron |
|
2.76060e-02 |
2.053e-02 |
Conversion electron |
|
2.77963e-02 |
1.202e-02 |
Conversion electron |
|
3.26700e-02 |
6.491e-02 |
Conversion electron |
|
3.72860e-02 |
3.404e-02 |
Conversion electron |
|
3.86420e-02 |
1.969e-02 |
Conversion electron |
|
3.90463e-02 |
2.450e-02 |
Conversion electron |
|
5.00160e-02 |
2.627e-02 |
Conversion electron |
|
5.02700e-02 |
3.082e-02 |
Conversion electron |
|
5.20890e-02 |
4.492e-02 |
Conversion electron |
|
5.27443e-02 |
1.005e-02 |
Conversion electron |
|
5.33740e-02 |
2.543e-02 |
Conversion electron |
|
5.65300e-02 |
9.122e-02 |
Conversion electron |
|
5.96340e-02 |
7.320e-02 |
Conversion electron |
|
6.50563e-02 |
1.559e-02 |
Conversion electron |
|
6.70180e-02 |
4.350e-02 |
Conversion electron |
|
6.71680e-02 |
8.872e-02 |
Conversion electron |
|
6.76900e-02 |
1.168e-02 |
Conversion electron |
|
6.84262e-02 |
1.145e-02 |
Auger electron |
|
7.13163e-02 |
4.559e-02 |
Conversion electron |
|
7.50900e-02 |
1.538e-02 |
Conversion electron |
|
8.24763e-02 |
1.505e-02 |
Conversion electron |
|
8.26263e-02 |
2.364e-02 |
Conversion electron |
|
8.78760e-02 |
1.390e-02 |
Conversion electron |
|
8.91890e-02 |
9.146e-02 |
Conversion electron |
|
1.06533e-01 |
4.520e-02 |
Conversion electron |
|
1.17758e-01 |
1.081e-02 |
Conversion electron |
|
1.74277e-01 |
1.512e-02 |
Conversion electron |
|
4.79825e+00 |
1.484e-02 |
Alpha |
|
4.81453e+00 |
9.200e-02 |
Alpha |
|
4.83847e+00 |
4.946e-02 |
Alpha |
|
4.84565e+00 |
5.559e-01 |
Alpha |
|
4.90116e+00 |
1.009e-01 |
Alpha |
|
4.96812e+00 |
5.906e-02 |
Alpha |
|
4.97903e+00 |
3.136e-02 |
Alpha |
|
5.05280e+00 |
6.529e-02 |
Alpha |
|
8.53577e-02 |
1.484e-02 |
Alpha recoil |
|
8.56473e-02 |
9.200e-02 |
Alpha recoil |
|
8.60731e-02 |
4.946e-02 |
Alpha recoil |
|
8.62009e-02 |
5.559e-01 |
Alpha recoil |
|
8.71884e-02 |
1.009e-01 |
Alpha recoil |
|
8.83796e-02 |
5.906e-02 |
Alpha recoil |
|
8.85736e-02 |
3.136e-02 |
Alpha recoil |
|
8.98860e-02 |
6.529e-02 |
Alpha recoil |
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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