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Radionuclide Dosimetric Data Sheets
Actinium-227
Summary data
General
Classification
Isotope: Ac-227
Atomic number (Z): 89
Mass number (A): 227
Neutron number (N): 138
Radioactive decay
Decay modes: α, β-
Half-life: 21.77 [y]
Decay constant: 1.0089e-09 [1/s]
Daughters: Th-227 (98.6%), Fr-223 (1.38%)
Radioactive daughters: Th-227, Fr-223
Dosimetric constants
Mean alpha energy: 0.0692 [MeV]
Mean electron energy: 0.01502 [MeV]
Mean photon energy: 0.00105 [MeV]
Air kerma rate constant, Γ10: 1.009e-18 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 1.009e-18 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 1.349e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for alphas, Δα: 1.109e-14
[Gy·kg/Bq·s]
Equilibrium dose constant for betas/electrons, Δβ-,β+,e-:
2.406e-15 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 1.682e-16
[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/Ac-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/Ac-227 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/Ac-227 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/Ac-227 Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
6.06235e-05 |
9.788e-02 |
X-ray |
|
8.21691e-05 |
4.166e+00 |
X-ray |
|
3.09793e-03 |
1.977e-02 |
X-ray |
|
1.29764e-02 |
1.361e-02 |
X-ray |
|
5.10703e-03 |
9.932e-02 |
Beta |
|
8.98118e-03 |
3.476e-01 |
Beta |
|
1.13798e-02 |
5.363e-01 |
Beta |
|
3.08189e-05 |
2.688e-02 |
Auger electron |
|
5.13707e-05 |
1.019e+00 |
Auger electron |
|
1.19525e-04 |
2.760e-02 |
Auger electron |
|
1.36440e-04 |
1.094e+00 |
Auger electron |
|
1.84108e-04 |
1.593e-02 |
Auger electron |
|
1.89763e-04 |
6.512e-01 |
Auger electron |
|
5.09114e-04 |
2.503e-01 |
Auger electron |
|
1.36535e-03 |
3.656e-02 |
Auger electron |
|
2.37396e-03 |
3.166e-01 |
Auger electron |
|
2.83060e-03 |
5.707e-02 |
Auger electron |
|
4.02200e-03 |
4.715e-02 |
Conversion electron |
|
4.72000e-03 |
1.507e-02 |
Conversion electron |
|
5.26380e-03 |
2.614e-01 |
Conversion electron |
|
8.18500e-03 |
1.071e-02 |
Conversion electron |
|
9.30000e-03 |
8.965e-02 |
Conversion electron |
|
9.87300e-03 |
2.519e-02 |
Auger electron |
|
1.30167e-02 |
1.255e-02 |
Auger electron |
|
2.04638e-02 |
1.825e-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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