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Radionuclide Dosimetric Data Sheets
Radium-225
Summary data
General
Classification
Isotope: Ra-225
Atomic number (Z): 88
Mass number (A): 225
Neutron number (N): 137
Radioactive decay
Decay modes: β-
Half-life: 14.9 [d]
Decay constant: 5.3843e-07 [1/s]
Daughters: Ac-225 (100.0%)
Radioactive daughters: Ac-225
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 0.10496 [MeV]
Mean photon energy: 0.01446 [MeV]
Air kerma rate constant, Γ10: 5.144e-18 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 5.144e-18 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 1.682e-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-:
1.682e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 2.317e-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/Ra-225 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/Ra-225 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/Ra-225 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/Ra-225 Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
7.95617e-05 |
4.512e+00 |
X-ray |
|
2.97177e-03 |
2.404e-02 |
X-ray |
|
1.26589e-02 |
5.452e-02 |
X-ray |
|
1.52434e-02 |
1.117e-02 |
X-ray |
|
1.57834e-02 |
3.750e-02 |
X-ray |
|
4.00000e-02 |
3.000e-01 |
Gamma |
|
8.77214e-02 |
6.949e-01 |
Beta |
|
1.00082e-01 |
3.049e-01 |
Beta |
|
3.11068e-05 |
1.028e+00 |
Auger electron |
|
1.25209e-04 |
1.222e+00 |
Auger electron |
|
1.86188e-04 |
6.787e-01 |
Auger electron |
|
4.78256e-04 |
1.793e-01 |
Auger electron |
|
1.31799e-03 |
7.796e-02 |
Auger electron |
|
2.26392e-03 |
3.956e-01 |
Auger electron |
|
2.65420e-03 |
6.554e-02 |
Auger electron |
|
9.56088e-03 |
1.020e-01 |
Auger electron |
|
1.25890e-02 |
5.012e-02 |
Auger electron |
|
2.01520e-02 |
8.683e-02 |
Conversion electron |
|
2.08370e-02 |
9.746e-02 |
Conversion electron |
|
2.41170e-02 |
1.138e-01 |
Conversion electron |
|
3.60961e-02 |
7.442e-02 |
Conversion electron |
|
4.00000e-02 |
2.467e-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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