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Radionuclide Dosimetric Data Sheets
Neptunium-239
Summary data
General
Classification
Isotope: Np-239
Atomic number (Z): 93
Mass number (A): 239
Neutron number (N): 146
Radioactive decay
Decay modes: β-
Half-life: 2.357 [d]
Decay constant: 3.4044e-06 [1/s]
Daughters: Pu-239 (100.0%)
Radioactive daughters: Pu-239
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 0.2623 [MeV]
Mean photon energy: 0.1846 [MeV]
Air kerma rate constant, Γ10: 1.829e-17 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 1.829e-17 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 4.203e-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-:
4.203e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 2.958e-14
[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-239 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-239 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-239 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-239 Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
7.19418e-05 |
2.219e+01 |
X-ray |
|
3.47094e-03 |
1.320e-01 |
X-ray |
|
1.21689e-02 |
1.558e-02 |
X-ray |
|
1.40932e-02 |
2.476e-02 |
X-ray |
|
1.42941e-02 |
2.174e-01 |
X-ray |
|
1.72768e-02 |
4.626e-02 |
X-ray |
|
1.75735e-02 |
1.372e-02 |
X-ray |
|
1.83932e-02 |
1.600e-01 |
X-ray |
|
1.85721e-02 |
1.127e-02 |
X-ray |
|
2.15285e-02 |
3.693e-02 |
X-ray |
|
6.14600e-02 |
1.290e-02 |
Gamma |
|
9.99790e-02 |
1.543e-01 |
X-ray |
|
1.04279e-01 |
2.443e-01 |
X-ray |
|
1.06123e-01 |
2.720e-01 |
Gamma |
|
1.16802e-01 |
2.833e-02 |
X-ray |
|
1.17801e-01 |
5.557e-02 |
X-ray |
|
1.21244e-01 |
1.455e-02 |
X-ray |
|
2.09753e-01 |
3.420e-02 |
Gamma |
|
2.28183e-01 |
1.076e-01 |
Gamma |
|
2.77599e-01 |
1.438e-01 |
Gamma |
|
3.15880e-01 |
1.600e-02 |
Gamma |
|
3.34310e-01 |
2.070e-02 |
Gamma |
|
5.66482e-02 |
1.532e-02 |
Beta |
|
9.23438e-02 |
3.928e-01 |
Beta |
|
1.11347e-01 |
1.067e-01 |
Beta |
|
1.25455e-01 |
4.364e-01 |
Beta |
|
2.00929e-01 |
1.940e-02 |
Beta |
|
2.17928e-01 |
1.940e-02 |
Beta |
|
8.89120e-05 |
6.188e+00 |
Auger electron |
|
1.76776e-04 |
3.874e-02 |
Auger electron |
|
1.96202e-04 |
3.421e+00 |
Auger electron |
|
2.44008e-04 |
5.767e+00 |
Auger electron |
|
6.45553e-04 |
1.312e+00 |
Auger electron |
|
1.69200e-03 |
2.492e-01 |
Auger electron |
|
2.58384e-03 |
1.723e+00 |
Auger electron |
|
3.13596e-03 |
3.583e-01 |
Auger electron |
|
3.30010e-03 |
5.056e-01 |
Conversion electron |
|
3.81874e-03 |
2.186e-02 |
Auger electron |
|
7.85000e-03 |
1.842e-01 |
Conversion electron |
|
1.06740e-02 |
3.256e-01 |
Auger electron |
|
1.38501e-02 |
2.158e-02 |
Conversion electron |
|
1.42173e-02 |
1.688e-01 |
Auger electron |
|
1.78001e-02 |
2.057e-02 |
Auger electron |
|
2.15380e-02 |
5.493e-02 |
Conversion electron |
|
2.22890e-02 |
2.039e-02 |
Conversion electron |
|
2.62880e-02 |
3.537e-02 |
Conversion electron |
|
2.65890e-02 |
1.270e-02 |
Conversion electron |
|
2.70390e-02 |
5.030e-02 |
Conversion electron |
|
3.13390e-02 |
3.911e-02 |
Conversion electron |
|
3.49090e-02 |
1.161e-01 |
Conversion electron |
|
3.92090e-02 |
9.312e-02 |
Conversion electron |
|
4.01101e-02 |
2.247e-02 |
Conversion electron |
|
4.48601e-02 |
3.358e-02 |
Conversion electron |
|
4.54890e-02 |
3.725e-02 |
Conversion electron |
|
4.94100e-02 |
1.206e-02 |
Conversion electron |
|
4.97890e-02 |
2.835e-02 |
Conversion electron |
|
5.27301e-02 |
5.992e-02 |
Conversion electron |
|
5.72800e-02 |
2.140e-02 |
Conversion electron |
|
6.33101e-02 |
1.883e-02 |
Conversion electron |
|
7.91086e-02 |
1.020e-02 |
Auger electron |
|
8.30010e-02 |
2.546e-02 |
Conversion electron |
|
8.37520e-02 |
1.487e-02 |
Conversion electron |
|
8.74030e-02 |
9.558e-02 |
Conversion electron |
|
8.80520e-02 |
1.261e-02 |
Conversion electron |
|
1.01573e-01 |
1.313e-02 |
Conversion electron |
|
1.05833e-01 |
2.384e-01 |
Conversion electron |
|
1.55249e-01 |
1.800e-01 |
Conversion electron |
|
1.86631e-01 |
1.687e-02 |
Conversion electron |
|
2.05061e-01 |
4.184e-02 |
Conversion electron |
|
2.23633e-01 |
1.141e-02 |
Conversion electron |
|
2.54477e-01 |
3.147e-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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