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Radionuclide Dosimetric Data Sheets
Thorium-236
Summary data
General
Classification
Isotope: Th-236
Atomic number (Z): 90
Mass number (A): 236
Neutron number (N): 146
Radioactive decay
Decay modes: β-
Half-life: 37.5 [m]
Decay constant: 3.0807e-04 [1/s]
Daughters: Pa-236 (100.0%)
Radioactive daughters: Pa-236
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 0.36705 [MeV]
Mean photon energy: 0.03463 [MeV]
Air kerma rate constant, Γ10: 2.959e-18 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 2.959e-18 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 5.881e-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-:
5.881e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 5.548e-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/Th-236 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-236 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/Th-236 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/Th-236 Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
7.65028e-05 |
2.281e+00 |
X-ray |
|
3.15673e-03 |
1.312e-02 |
X-ray |
|
1.32994e-02 |
2.720e-02 |
X-ray |
|
1.67859e-02 |
1.248e-02 |
X-ray |
|
9.63371e-02 |
1.540e-02 |
X-ray |
|
1.10800e-01 |
4.200e-02 |
Gamma |
|
1.24464e-01 |
1.529e-02 |
Beta |
|
2.38698e-01 |
5.097e-02 |
Beta |
|
3.21811e-01 |
9.174e-02 |
Beta |
|
3.63162e-01 |
8.359e-01 |
Beta |
|
6.46231e-05 |
5.564e-01 |
Auger electron |
|
1.65263e-04 |
6.034e-01 |
Auger electron |
|
1.93697e-04 |
3.379e-01 |
Auger electron |
|
5.27541e-04 |
9.908e-02 |
Auger electron |
|
1.39056e-03 |
6.463e-02 |
Auger electron |
|
2.37537e-03 |
1.964e-01 |
Auger electron |
|
2.81837e-03 |
3.528e-02 |
Auger electron |
|
1.00071e-02 |
4.599e-02 |
Auger electron |
|
1.10980e-02 |
1.280e-02 |
Conversion electron |
|
1.32435e-02 |
2.312e-02 |
Auger electron |
|
1.47570e-02 |
1.236e-02 |
Conversion electron |
|
8.29200e-02 |
1.790e-02 |
Conversion electron |
|
8.96870e-02 |
4.831e-02 |
Conversion electron |
|
9.16870e-02 |
2.436e-02 |
Conversion electron |
|
1.06641e-01 |
1.300e-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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