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Radionuclide Dosimetric Data Sheets
Neptunium-236m
Summary data
General
Classification
Isotope: Np-236m
Atomic number (Z): 93
Mass number (A): 236
Neutron number (N): 143
Radioactive decay
Decay modes: β-, Electron capture
Half-life: 22.5 [h]
Decay constant: 8.5574e-06 [1/s]
Daughters: U-236 (52.0%), Pu-236 (48.0%)
Radioactive daughters: U-236, Pu-236
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 0.08802 [MeV]
Mean photon energy: 0.05066 [MeV]
Air kerma rate constant, Γ10: 7.967e-18 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 7.967e-18 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 1.410e-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-:
1.410e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 8.117e-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-236m 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-236m 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-236m 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-236m Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
7.20459e-05 |
8.275e-01 |
X-ray |
|
7.54646e-05 |
6.620e+00 |
X-ray |
|
3.24997e-03 |
4.033e-02 |
X-ray |
|
1.34452e-02 |
1.093e-02 |
X-ray |
|
1.36268e-02 |
9.599e-02 |
X-ray |
|
1.42941e-02 |
1.115e-02 |
X-ray |
|
1.64468e-02 |
2.013e-02 |
X-ray |
|
1.73072e-02 |
5.779e-02 |
X-ray |
|
1.83932e-02 |
1.198e-02 |
X-ray |
|
2.02658e-02 |
1.309e-02 |
X-ray |
|
9.50660e-02 |
1.131e-01 |
X-ray |
|
9.89281e-02 |
1.809e-01 |
X-ray |
|
1.10929e-01 |
2.087e-02 |
X-ray |
|
1.11820e-01 |
4.081e-02 |
X-ray |
|
1.15080e-01 |
1.056e-02 |
X-ray |
|
1.44405e-01 |
8.300e-02 |
Beta |
|
1.59016e-01 |
3.970e-01 |
Beta |
|
7.22012e-05 |
1.785e+00 |
Auger electron |
|
8.91208e-05 |
2.265e-01 |
Auger electron |
|
1.62919e-04 |
1.138e-02 |
Auger electron |
|
1.85399e-04 |
1.746e+00 |
Auger electron |
|
1.91649e-04 |
1.292e-01 |
Auger electron |
|
1.92204e-04 |
9.923e-01 |
Auger electron |
|
2.36973e-04 |
2.171e-01 |
Auger electron |
|
5.35973e-04 |
2.582e-01 |
Auger electron |
|
5.73608e-04 |
3.351e-02 |
Auger electron |
|
1.42537e-03 |
1.046e-01 |
Auger electron |
|
2.43117e-03 |
5.778e-01 |
Auger electron |
|
2.56520e-03 |
7.105e-02 |
Auger electron |
|
2.90043e-03 |
1.083e-01 |
Auger electron |
|
3.09862e-03 |
1.459e-02 |
Auger electron |
|
1.00799e-02 |
1.475e-01 |
Auger electron |
|
1.07769e-02 |
1.758e-02 |
Auger electron |
|
1.34002e-02 |
7.488e-02 |
Auger electron |
|
2.22590e-02 |
3.197e-02 |
Conversion electron |
|
2.42360e-02 |
2.762e-02 |
Conversion electron |
|
2.65590e-02 |
2.736e-02 |
Conversion electron |
|
2.80980e-02 |
2.433e-02 |
Conversion electron |
|
4.00801e-02 |
1.691e-02 |
Conversion electron |
|
4.09904e-02 |
1.463e-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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