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Radionuclide Dosimetric Data Sheets
Thallium-209
Summary data
General
Classification
Isotope: Tl-209
Atomic number (Z): 81
Mass number (A): 209
Neutron number (N): 128
Radioactive decay
Decay modes: β-
Half-life: 2.161 [m]
Decay constant: 5.3459e-03 [1/s]
Daughters: Pb-209 (100.0%)
Radioactive daughters: Pb-209
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 0.68754 [MeV]
Mean photon energy: 2.14263 [MeV]
Air kerma rate constant, Γ10: 7.521e-17 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 7.521e-17 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 1.102e-13 [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-:
1.102e-13 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 3.433e-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/Tl-209 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/Tl-209 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/Tl-209 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/Tl-209 Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
2.66218e-05 |
3.478e+00 |
X-ray |
|
2.37981e-03 |
1.313e-02 |
X-ray |
|
1.05510e-02 |
3.732e-02 |
X-ray |
|
1.26563e-02 |
2.573e-02 |
X-ray |
|
7.30390e-02 |
6.347e-02 |
X-ray |
|
7.52501e-02 |
1.066e-01 |
X-ray |
|
8.47407e-02 |
1.188e-02 |
X-ray |
|
8.52354e-02 |
2.300e-02 |
X-ray |
|
1.17211e-01 |
8.430e-01 |
Gamma |
|
4.65130e-01 |
9.690e-01 |
Gamma |
|
1.56709e+00 |
9.981e-01 |
Gamma |
|
6.59806e-01 |
9.883e-01 |
Beta |
|
4.21815e-05 |
7.808e-01 |
Auger electron |
|
8.21772e-05 |
1.126e+00 |
Auger electron |
|
1.73791e-04 |
5.943e-01 |
Auger electron |
|
4.20901e-04 |
1.306e-01 |
Auger electron |
|
1.03152e-03 |
3.375e-02 |
Auger electron |
|
1.91093e-03 |
3.173e-01 |
Auger electron |
|
2.17132e-03 |
3.957e-02 |
Auger electron |
|
8.04677e-03 |
9.521e-02 |
Auger electron |
|
1.04212e-02 |
4.211e-02 |
Auger electron |
|
2.89210e-02 |
1.988e-01 |
Conversion electron |
|
1.01364e-01 |
2.252e-02 |
Conversion electron |
|
3.76840e-01 |
2.365e-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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