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Radionuclide Dosimetric Data Sheets
Americium-238
Summary data
General
Classification
Isotope: Am-238
Atomic number (Z): 95
Mass number (A): 238
Neutron number (N): 143
Radioactive decay
Decay modes: α, β+, Electron capture
Half-life: 98.0 [m]
Decay constant: 1.1788e-04 [1/s]
Daughters: Pu-238 (100.0%), Np-234 (0.0001%)
Radioactive daughters: Pu-238, Np-234
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 0.04851 [MeV]
Mean photon energy: 0.90232 [MeV]
Air kerma rate constant, Γ10: 4.504e-17 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 4.509e-17 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 7.772e-15 [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-:
7.772e-15 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 1.446e-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/Am-238 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/Am-238 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/Am-238 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/Am-238 Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
7.20040e-05 |
1.645e+01 |
X-ray |
|
3.44815e-03 |
1.081e-01 |
X-ray |
|
1.21689e-02 |
1.740e-02 |
X-ray |
|
1.40932e-02 |
2.766e-02 |
X-ray |
|
1.42941e-02 |
2.429e-01 |
X-ray |
|
1.72768e-02 |
5.167e-02 |
X-ray |
|
1.75735e-02 |
1.137e-02 |
X-ray |
|
1.79611e-02 |
1.006e-02 |
X-ray |
|
1.83932e-02 |
1.748e-01 |
X-ray |
|
2.15285e-02 |
4.034e-02 |
X-ray |
|
9.99790e-02 |
2.245e-01 |
X-ray |
|
1.04279e-01 |
3.553e-01 |
X-ray |
|
1.16802e-01 |
4.121e-02 |
X-ray |
|
1.17801e-01 |
8.084e-02 |
X-ray |
|
1.20980e-01 |
1.038e-02 |
X-ray |
|
1.21244e-01 |
2.116e-02 |
X-ray |
|
3.57700e-01 |
2.100e-02 |
Gamma |
|
5.61000e-01 |
1.092e-01 |
Gamma |
|
6.05100e-01 |
7.560e-02 |
Gamma |
|
9.18700e-01 |
2.296e-01 |
Gamma |
|
9.41400e-01 |
2.240e-02 |
Gamma |
|
9.62800e-01 |
2.800e-01 |
Gamma |
|
1.26620e+00 |
1.680e-02 |
Gamma |
|
1.57730e+00 |
2.884e-02 |
Gamma |
|
1.63660e+00 |
1.260e-02 |
Gamma |
|
8.90995e-05 |
4.508e+00 |
Auger electron |
|
1.76265e-04 |
2.839e-02 |
Auger electron |
|
1.91646e-04 |
2.547e+00 |
Auger electron |
|
2.36156e-04 |
4.320e+00 |
Auger electron |
|
5.67958e-04 |
6.646e-01 |
Auger electron |
|
1.66493e-03 |
2.309e-01 |
Auger electron |
|
2.55493e-03 |
1.416e+00 |
Auger electron |
|
3.08597e-03 |
2.900e-01 |
Auger electron |
|
3.74288e-03 |
1.741e-02 |
Auger electron |
|
1.06143e-02 |
3.558e-01 |
Auger electron |
|
1.41516e-02 |
1.844e-01 |
Auger electron |
|
1.77248e-02 |
2.245e-02 |
Auger electron |
|
2.17290e-02 |
1.983e-01 |
Conversion electron |
|
2.60290e-02 |
1.702e-01 |
Conversion electron |
|
3.95501e-02 |
1.050e-01 |
Conversion electron |
|
4.41000e-02 |
3.745e-02 |
Conversion electron |
|
7.91086e-02 |
1.483e-02 |
Auger 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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