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Radionuclide Dosimetric Data Sheets

Americium-241

Summary data

General

Classification

Isotope:  Am-241
Atomic number (Z):  95
Mass number (A):  241
Neutron number (N):  146

Radioactive decay

Decay modes:  α
Half-life:  432.2 [y]
Decay constant:  5.0821e-11 [1/s]
Daughters:  Np-237 (100.0%)
Radioactive daughters:  Np-237

Dosimetric constants

Mean alpha energy:  5.5712 [MeV]
Mean electron energy:  0.0373 [MeV]
Mean photon energy:  0.02933 [MeV]
Air kerma rate constant, Γ10:  9.803e-18 [Gy·m2/Bq·s]
Air kerma coefficient, Kair:  9.803e-18 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or electrons), Δwp:  8.986e-13 [Gy·kg/Bq·s]
Equilibrium dose constant for alphas, Δα:  8.926e-13 [Gy·kg/Bq·s]
Equilibrium dose constant for betas/electrons, Δβ-,β+,e-:  5.976e-15 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp:  4.699e-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-241 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-241 Summary 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-241 Summary Spectrum.csv

 

Energy [MeV]

Yield [#/nt] if > 0.01

Radiation type

7.44386e-05

1.115e+01

X-ray

3.34952e-03

7.016e-02

X-ray

1.19138e-02

1.026e-02

X-ray

1.37668e-02

1.651e-02

X-ray

1.39579e-02

1.450e-01

X-ray

1.68587e-02

3.064e-02

X-ray

1.70745e-02

1.625e-02

X-ray

1.78428e-02

8.828e-02

X-ray

1.80184e-02

1.375e-02

X-ray

2.08890e-02

2.018e-02

X-ray

2.63448e-02

2.400e-02

Gamma

5.95412e-02

3.590e-01

Gamma

7.89857e-05

3.264e+00

Auger electron

1.70006e-04

1.941e-02

Auger electron

1.90572e-04

1.699e+00

Auger electron

2.09123e-04

2.933e+00

Auger electron

5.73102e-04

4.626e-01

Auger electron

1.61346e-03

2.514e-01

Auger electron

2.49042e-03

9.591e-01

Auger electron

2.99076e-03

1.877e-01

Auger electron

3.62968e-03

1.118e-02

Auger electron

3.90480e-03

2.569e-02

Conversion electron

4.64280e-03

5.033e-02

Conversion electron

8.71880e-03

6.597e-02

Conversion electron

1.04706e-02

2.276e-01

Auger electron

1.07560e-02

1.176e-01

Conversion electron

1.14940e-02

3.556e-02

Conversion electron

1.39131e-02

1.169e-01

Auger electron

1.55700e-02

2.209e-02

Conversion electron

1.73991e-02

1.414e-02

Auger electron

2.09830e-02

2.786e-02

Conversion electron

2.17210e-02

3.480e-02

Conversion electron

2.19232e-02

3.735e-02

Conversion electron

2.57970e-02

2.818e-02

Conversion electron

2.63448e-02

1.266e-02

Conversion electron

2.87744e-02

4.428e-02

Conversion electron

3.31960e-02

1.596e-02

Conversion electron

3.71012e-02

1.100e-01

Conversion electron

3.78392e-02

1.002e-01

Conversion electron

3.90014e-02

2.420e-02

Conversion electron

4.19152e-02

1.015e-01

Conversion electron

5.51196e-02

7.779e-02

Conversion electron

5.95412e-02

2.697e-02

Conversion electron

5.38830e+00

1.604e-02

Alpha

5.44293e+00

1.303e-01

Alpha

5.48562e+00

8.473e-01

Alpha

9.10009e-02

1.604e-02

Alpha recoil

9.19235e-02

1.303e-01

Alpha recoil

9.26446e-02

8.473e-01

Alpha recoil

 

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

 

 

 

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