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Radionuclide Dosimetric Data Sheets
Polonium-205
Summary data
General
Classification
Isotope: Po-205
Atomic number (Z): 84
Mass number (A): 205
Neutron number (N): 121
Radioactive decay
Decay modes: α, β+, Electron capture
Half-life: 1.66 [h]
Decay constant: 1.1599e-04 [1/s]
Daughters: Bi-205 (99.9%), Pb-201 (0.04%)
Radioactive daughters: Bi-205, Pb-201
Dosimetric constants
Mean alpha energy: 0.0021 [MeV]
Mean electron energy: 0.06602 [MeV]
Mean photon energy: 1.58456 [MeV]
Air kerma rate constant, Γ10: 7.024e-17 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 7.112e-17 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 1.091e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for alphas, Δα: 3.365e-16
[Gy·kg/Bq·s]
Equilibrium dose constant for betas/electrons, Δβ-,β+,e-:
1.058e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 2.539e-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/Po-205 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/Po-205 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/Po-205 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/Po-205 Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
3.24796e-05 |
1.505e+01 |
X-ray |
|
2.46029e-03 |
6.018e-02 |
X-ray |
|
9.45110e-03 |
1.055e-02 |
X-ray |
|
1.07270e-02 |
1.845e-02 |
X-ray |
|
1.08390e-02 |
1.625e-01 |
X-ray |
|
1.29844e-02 |
3.155e-02 |
X-ray |
|
1.30700e-02 |
1.020e-01 |
X-ray |
|
1.53031e-02 |
2.106e-02 |
X-ray |
|
7.50642e-02 |
2.615e-01 |
X-ray |
|
7.74071e-02 |
4.373e-01 |
X-ray |
|
8.71393e-02 |
4.890e-02 |
X-ray |
|
8.76651e-02 |
9.477e-02 |
X-ray |
|
9.00323e-02 |
1.173e-02 |
X-ray |
|
9.01629e-02 |
2.310e-02 |
X-ray |
|
1.28900e-01 |
1.109e-02 |
Gamma |
|
1.51400e-01 |
1.331e-02 |
Gamma |
|
2.12000e-01 |
3.585e-02 |
Gamma |
|
2.61000e-01 |
4.029e-02 |
Gamma |
|
5.11000e-01 |
4.565e-02 |
Annihilation photon |
|
5.99800e-01 |
2.624e-02 |
Gamma |
|
6.14200e-01 |
1.589e-02 |
Gamma |
|
6.24800e-01 |
1.035e-02 |
Gamma |
|
8.36800e-01 |
1.922e-01 |
Gamma |
|
8.49800e-01 |
2.550e-01 |
Gamma |
|
8.72400e-01 |
3.696e-01 |
Gamma |
|
1.00120e+00 |
2.883e-01 |
Gamma |
|
1.18350e+00 |
1.220e-02 |
Gamma |
|
1.23910e+00 |
4.620e-02 |
Gamma |
|
1.33640e+00 |
1.331e-02 |
Gamma |
|
1.51370e+00 |
2.107e-02 |
Gamma |
|
1.55180e+00 |
2.920e-02 |
Gamma |
|
1.72920e+00 |
1.552e-02 |
Gamma |
|
1.81130e+00 |
1.183e-02 |
Gamma |
|
6.89947e-01 |
1.368e-02 |
Positron |
|
4.07258e-05 |
3.505e+00 |
Auger electron |
|
8.95175e-05 |
4.785e+00 |
Auger electron |
|
1.73702e-04 |
2.549e+00 |
Auger electron |
|
4.26992e-04 |
5.828e-01 |
Auger electron |
|
1.00532e-03 |
1.954e-01 |
Auger electron |
|
1.96190e-03 |
1.368e+00 |
Auger electron |
|
2.23853e-03 |
1.798e-01 |
Auger electron |
|
6.22400e-03 |
2.658e-02 |
Conversion electron |
|
7.43310e-03 |
2.350e-02 |
Conversion electron |
|
8.24484e-03 |
3.913e-01 |
Auger electron |
|
1.07071e-02 |
1.759e-01 |
Auger electron |
|
1.31976e-02 |
1.889e-02 |
Auger electron |
|
3.80680e-02 |
4.723e-02 |
Conversion electron |
|
6.03003e-02 |
2.167e-02 |
Auger electron |
|
6.05680e-02 |
3.591e-02 |
Conversion electron |
|
7.26460e-02 |
1.191e-02 |
Auger electron |
|
1.70168e-01 |
2.368e-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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