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Radionuclide Dosimetric Data Sheets
Thorium-227
Summary data
General
Classification
Isotope: Th-227
Atomic number (Z): 90
Mass number (A): 227
Neutron number (N): 137
Radioactive decay
Decay modes: α
Half-life: 18.68 [d]
Decay constant: 4.2947e-07 [1/s]
Daughters: Ra-223 (100.0%)
Radioactive daughters: Ra-223
Dosimetric constants
Mean alpha energy: 5.9882 [MeV]
Mean electron energy: 0.07547 [MeV]
Mean photon energy: 0.13174 [MeV]
Air kerma rate constant, Γ10: 2.110e-17 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 2.110e-17 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 9.715e-13 [Gy·kg/Bq·s]
Equilibrium dose constant for alphas, Δα: 9.594e-13
[Gy·kg/Bq·s]
Equilibrium dose constant for betas/electrons, Δβ-,β+,e-:
1.209e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 2.111e-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-227 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-227 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-227 Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
7.12272e-05 |
1.763e+01 |
X-ray |
|
2.88731e-03 |
8.987e-02 |
X-ray |
|
1.06609e-02 |
1.313e-02 |
X-ray |
|
1.21973e-02 |
2.235e-02 |
X-ray |
|
1.23447e-02 |
1.966e-01 |
X-ray |
|
1.48529e-02 |
3.993e-02 |
X-ray |
|
1.53013e-02 |
1.821e-01 |
X-ray |
|
1.79232e-02 |
3.965e-02 |
X-ray |
|
5.01300e-02 |
8.385e-02 |
Gamma |
|
7.96900e-02 |
1.948e-02 |
Gamma |
|
8.57602e-02 |
2.613e-02 |
X-ray |
|
8.88641e-02 |
4.268e-02 |
X-ray |
|
9.38800e-02 |
1.511e-02 |
Gamma |
|
2.10620e-01 |
1.251e-02 |
Gamma |
|
2.35960e-01 |
1.290e-01 |
Gamma |
|
2.56230e-01 |
7.005e-02 |
Gamma |
|
2.86090e-01 |
1.741e-02 |
Gamma |
|
2.89590e-01 |
1.935e-02 |
Gamma |
|
2.99980e-01 |
2.206e-02 |
Gamma |
|
3.04500e-01 |
1.148e-02 |
Gamma |
|
3.29850e-01 |
2.941e-02 |
Gamma |
|
3.34370e-01 |
1.135e-02 |
Gamma |
|
2.56800e-05 |
4.850e+00 |
Auger electron |
|
1.20625e-04 |
4.901e+00 |
Auger electron |
|
1.35431e-04 |
2.149e-02 |
Auger electron |
|
1.81389e-04 |
2.775e+00 |
Auger electron |
|
4.71973e-04 |
7.105e-01 |
Auger electron |
|
1.46488e-03 |
1.933e-01 |
Auger electron |
|
2.22033e-03 |
1.553e+00 |
Auger electron |
|
2.59290e-03 |
2.499e-01 |
Auger electron |
|
2.72630e-03 |
2.870e-02 |
Conversion electron |
|
3.12076e-03 |
1.401e-02 |
Auger electron |
|
9.42461e-03 |
4.057e-01 |
Auger electron |
|
1.06280e-02 |
5.512e-02 |
Conversion electron |
|
1.10400e-02 |
4.097e-02 |
Conversion electron |
|
1.13000e-02 |
1.374e-01 |
Conversion electron |
|
1.23480e-02 |
4.361e-02 |
Conversion electron |
|
1.23569e-02 |
1.967e-01 |
Auger electron |
|
1.30200e-02 |
5.004e-02 |
Conversion electron |
|
1.41440e-02 |
4.136e-02 |
Conversion electron |
|
1.44040e-02 |
1.341e-01 |
Conversion electron |
|
1.53240e-02 |
2.260e-02 |
Auger electron |
|
1.61240e-02 |
4.614e-02 |
Conversion electron |
|
2.49880e-02 |
1.085e-02 |
Conversion electron |
|
2.52400e-02 |
1.058e-01 |
Conversion electron |
|
2.56600e-02 |
2.158e-02 |
Conversion electron |
|
2.58263e-02 |
2.283e-02 |
Conversion electron |
|
2.60863e-02 |
8.619e-02 |
Conversion electron |
|
2.78063e-02 |
3.624e-02 |
Conversion electron |
|
2.83440e-02 |
9.925e-02 |
Conversion electron |
|
2.87640e-02 |
1.928e-02 |
Conversion electron |
|
2.97400e-02 |
1.698e-02 |
Conversion electron |
|
2.98600e-02 |
2.905e-02 |
Conversion electron |
|
3.08980e-02 |
1.563e-02 |
Conversion electron |
|
3.15700e-02 |
1.384e-02 |
Conversion electron |
|
3.15800e-02 |
1.229e-02 |
Conversion electron |
|
3.28440e-02 |
1.556e-02 |
Conversion electron |
|
3.46740e-02 |
1.532e-02 |
Conversion electron |
|
4.00263e-02 |
5.631e-02 |
Conversion electron |
|
4.04463e-02 |
1.364e-02 |
Conversion electron |
|
4.28810e-02 |
3.468e-02 |
Conversion electron |
|
4.32180e-02 |
1.686e-02 |
Conversion electron |
|
4.38000e-02 |
1.887e-02 |
Conversion electron |
|
4.59850e-02 |
2.967e-02 |
Conversion electron |
|
4.63563e-02 |
1.101e-02 |
Conversion electron |
|
5.76673e-02 |
1.779e-02 |
Conversion electron |
|
1.81770e-01 |
1.214e-02 |
Conversion electron |
|
1.85270e-01 |
1.305e-02 |
Conversion electron |
|
2.00180e-01 |
1.012e-02 |
Conversion electron |
|
5.66839e+00 |
2.054e-02 |
Alpha |
|
5.69370e+00 |
1.495e-02 |
Alpha |
|
5.70151e+00 |
3.619e-02 |
Alpha |
|
5.70958e+00 |
8.274e-02 |
Alpha |
|
5.71401e+00 |
4.875e-02 |
Alpha |
|
5.75701e+00 |
2.034e-01 |
Alpha |
|
5.80734e+00 |
1.266e-02 |
Alpha |
|
5.86656e+00 |
2.412e-02 |
Alpha |
|
5.95975e+00 |
2.991e-02 |
Alpha |
|
5.97771e+00 |
2.343e-01 |
Alpha |
|
6.00872e+00 |
2.891e-02 |
Alpha |
|
6.03805e+00 |
2.412e-01 |
Alpha |
|
1.01741e-01 |
2.054e-02 |
Alpha recoil |
|
1.02196e-01 |
1.495e-02 |
Alpha recoil |
|
1.02336e-01 |
3.619e-02 |
Alpha recoil |
|
1.02481e-01 |
8.274e-02 |
Alpha recoil |
|
1.02560e-01 |
4.875e-02 |
Alpha recoil |
|
1.03332e-01 |
2.034e-01 |
Alpha recoil |
|
1.04235e-01 |
1.266e-02 |
Alpha recoil |
|
1.05298e-01 |
2.412e-02 |
Alpha recoil |
|
1.06971e-01 |
2.991e-02 |
Alpha recoil |
|
1.07293e-01 |
2.343e-01 |
Alpha recoil |
|
1.07850e-01 |
2.891e-02 |
Alpha recoil |
|
1.08376e-01 |
2.412e-01 |
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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