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Radionuclide Dosimetric Data Sheets
Americium-244m
Summary data
General
Classification
Isotope: Am-244m
Atomic number (Z): 95
Mass number (A): 244
Neutron number (N): 149
Radioactive decay
Decay modes: β-
Half-life: 26.0 [m]
Decay constant: 4.4433e-04 [1/s]
Daughters: Cm-244 (100.0%)
Radioactive daughters: Cm-244
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 0.5187 [MeV]
Mean photon energy: 0.01719 [MeV]
Air kerma rate constant, Γ10: 3.088e-18 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 3.088e-18 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 8.311e-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-:
8.311e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 2.754e-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/Am-244m 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-244m 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-244m 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-244m Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
7.76477e-05 |
3.240e+00 |
X-ray |
|
3.66021e-03 |
2.288e-02 |
X-ray |
|
1.49784e-02 |
4.566e-02 |
X-ray |
|
1.95388e-02 |
4.941e-02 |
X-ray |
|
2.28564e-02 |
1.161e-02 |
X-ray |
|
1.55567e-01 |
1.437e-02 |
Beta |
|
4.95507e-01 |
3.080e-01 |
Beta |
|
5.12031e-01 |
6.674e-01 |
Beta |
|
9.71062e-05 |
9.168e-01 |
Auger electron |
|
1.90660e-04 |
4.903e-01 |
Auger electron |
|
2.79570e-04 |
8.502e-01 |
Auger electron |
|
6.00151e-04 |
1.404e-01 |
Auger electron |
|
1.80872e-03 |
3.008e-02 |
Auger electron |
|
2.67736e-03 |
2.750e-01 |
Auger electron |
|
3.27160e-03 |
6.092e-02 |
Auger electron |
|
1.12729e-02 |
6.719e-02 |
Auger electron |
|
1.50452e-02 |
3.555e-02 |
Auger electron |
|
1.91890e-02 |
1.239e-01 |
Conversion electron |
|
2.39710e-02 |
1.054e-01 |
Conversion electron |
|
3.81360e-02 |
6.517e-02 |
Conversion electron |
|
4.29650e-02 |
2.431e-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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