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Radionuclide Dosimetric Data Sheets
Neptunium-242
Summary data
General
Classification
Isotope: Np-242
Atomic number (Z): 93
Mass number (A): 242
Neutron number (N): 149
Radioactive decay
Decay modes: β-
Half-life: 2.2 [m]
Decay constant: 5.2511e-03 [1/s]
Daughters: Pu-242 (100.0%)
Radioactive daughters: Pu-242
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 0.90269 [MeV]
Mean photon energy: 0.26544 [MeV]
Air kerma rate constant, Γ10: 1.005e-17 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 1.005e-17 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 1.446e-13 [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-:
1.446e-13 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 4.253e-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-242 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-242 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-242 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-242 Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
7.20455e-05 |
1.291e+00 |
X-ray |
|
1.42941e-02 |
1.736e-02 |
X-ray |
|
1.83932e-02 |
1.866e-02 |
X-ray |
|
7.35930e-01 |
5.200e-02 |
Gamma |
|
7.80440e-01 |
2.756e-02 |
Gamma |
|
8.13600e-01 |
1.248e-02 |
Gamma |
|
1.09350e+00 |
1.196e-02 |
Gamma |
|
1.13710e+00 |
1.300e-02 |
Gamma |
|
1.47310e+00 |
2.340e-02 |
Gamma |
|
1.51760e+00 |
1.248e-02 |
Gamma |
|
1.04123e-01 |
1.604e-02 |
Beta |
|
2.30457e-01 |
1.103e-02 |
Beta |
|
2.57099e-01 |
1.403e-02 |
Beta |
|
3.87565e-01 |
2.205e-02 |
Beta |
|
5.16120e-01 |
1.704e-02 |
Beta |
|
6.74234e-01 |
4.911e-02 |
Beta |
|
9.90058e-01 |
8.319e-01 |
Beta |
|
8.91196e-05 |
3.533e-01 |
Auger electron |
|
1.91662e-04 |
2.015e-01 |
Auger electron |
|
2.36997e-04 |
3.387e-01 |
Auger electron |
|
5.74151e-04 |
5.230e-02 |
Auger electron |
|
1.48435e-03 |
1.225e-02 |
Auger electron |
|
2.56519e-03 |
1.108e-01 |
Auger electron |
|
3.09861e-03 |
2.275e-02 |
Auger electron |
|
1.07807e-02 |
2.741e-02 |
Auger electron |
|
1.43281e-02 |
1.423e-02 |
Auger electron |
|
2.21690e-02 |
4.596e-02 |
Conversion electron |
|
2.64690e-02 |
3.935e-02 |
Conversion electron |
|
3.99901e-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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