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Radionuclide Dosimetric Data Sheets
Neptunium-241
Summary data
General
Classification
Isotope: Np-241
Atomic number (Z): 93
Mass number (A): 241
Neutron number (N): 148
Radioactive decay
Decay modes: β-
Half-life: 13.9 [m]
Decay constant: 8.3111e-04 [1/s]
Daughters: Pu-241 (100.0%)
Radioactive daughters: Pu-241
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 0.4341 [MeV]
Mean photon energy: 0.03954 [MeV]
Air kerma rate constant, Γ10: 4.870e-18 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 4.870e-18 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 6.955e-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-:
6.955e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 6.335e-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/Np-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/Np-241 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/Np-241 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/Np-241 Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
7.19786e-05 |
4.642e+00 |
X-ray |
|
3.44543e-03 |
3.027e-02 |
X-ray |
|
1.42941e-02 |
6.712e-02 |
X-ray |
|
1.72768e-02 |
1.428e-02 |
X-ray |
|
1.83932e-02 |
3.729e-02 |
X-ray |
|
9.99790e-02 |
6.773e-02 |
X-ray |
|
1.04279e-01 |
1.072e-01 |
X-ray |
|
1.16802e-01 |
1.243e-02 |
X-ray |
|
1.17801e-01 |
2.439e-02 |
X-ray |
|
1.75100e-01 |
3.100e-02 |
Gamma |
|
3.66107e-01 |
3.230e-01 |
Beta |
|
4.32059e-01 |
6.656e-01 |
Beta |
|
8.90694e-05 |
1.274e+00 |
Auger electron |
|
1.91967e-04 |
7.143e-01 |
Auger electron |
|
2.36385e-04 |
1.219e+00 |
Auger electron |
|
5.77089e-04 |
1.918e-01 |
Auger electron |
|
1.74876e-03 |
9.298e-02 |
Auger electron |
|
2.55150e-03 |
3.974e-01 |
Auger electron |
|
3.08240e-03 |
8.132e-02 |
Auger electron |
|
1.06135e-02 |
9.764e-02 |
Auger electron |
|
1.07500e-02 |
8.728e-02 |
Conversion electron |
|
1.41545e-02 |
5.058e-02 |
Auger electron |
|
1.88780e-02 |
5.108e-02 |
Conversion electron |
|
1.96290e-02 |
1.638e-02 |
Conversion electron |
|
3.74501e-02 |
1.960e-02 |
Conversion electron |
|
5.27500e-02 |
1.442e-01 |
Conversion electron |
|
1.09978e-01 |
1.551e-02 |
Conversion electron |
|
1.51978e-01 |
2.551e-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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