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Radionuclide Dosimetric Data Sheets

Neptunium-242m

Summary data

General

Classification

Isotope:  Np-242m
Atomic number (Z):  93
Mass number (A):  242
Neutron number (N):  149

Radioactive decay

Decay modes:  β-
Half-life:  5.5 [m]
Decay constant:  2.1004e-03 [1/s]
Daughters:  Pu-242 (100.0%)
Radioactive daughters:  Pu-242

Dosimetric constants

Mean alpha energy:  0.0 [MeV]
Mean electron energy:  0.75505 [MeV]
Mean photon energy:  0.91935 [MeV]
Air kerma rate constant, Γ10:  5.234e-17 [Gy·m2/Bq·s]
Air kerma coefficient, Kair:  5.234e-17 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or electrons), Δwp:  1.210e-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-:  1.210e-13 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp:  1.473e-13 [Gy·kg/Bq·s]

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-242m 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-242m 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-242m Summary Spectrum.csv

 

Energy [MeV]

Yield [#/nt] if > 0.01

Radiation type

7.20518e-05

2.373e+01

X-ray

3.45913e-03

1.562e-01

X-ray

1.21689e-02

2.164e-02

X-ray

1.40932e-02

3.440e-02

X-ray

1.42941e-02

3.021e-01

X-ray

1.64689e-02

1.025e-02

X-ray

1.72768e-02

6.427e-02

X-ray

1.79612e-02

1.251e-02

X-ray

1.83932e-02

3.606e-01

X-ray

2.15284e-02

8.321e-02

X-ray

2.22515e-02

1.663e-02

X-ray

9.99790e-02

2.346e-02

X-ray

1.02800e-01

6.408e-02

Gamma

1.04279e-01

3.713e-02

X-ray

1.59100e-01

1.888e-01

Gamma

2.65100e-01

1.416e-01

Gamma

7.85700e-01

5.900e-01

Gamma

9.44800e-01

3.717e-01

Gamma

4.48389e-01

1.400e-01

Beta

5.51029e-01

8.600e-01

Beta

8.91100e-05

6.497e+00

Auger electron

1.76526e-04

4.091e-02

Auger electron

1.91846e-04

3.708e+00

Auger electron

2.37550e-04

6.226e+00

Auger electron

5.82536e-04

9.688e-01

Auger electron

1.50237e-03

2.491e-01

Auger electron

2.56799e-03

2.032e+00

Auger electron

3.10209e-03

4.173e-01

Auger electron

3.76379e-03

2.510e-02

Auger electron

1.08733e-02

4.965e-01

Auger electron

1.44280e-02

2.579e-01

Auger electron

1.80262e-02

3.153e-02

Auger electron

2.14180e-02

1.348e-02

Conversion electron

2.21690e-02

3.725e-01

Conversion electron

2.64690e-02

3.189e-01

Conversion electron

3.67500e-02

3.624e-02

Conversion electron

3.99901e-02

1.970e-01

Conversion electron

4.45400e-02

7.029e-02

Conversion electron

7.96780e-02

2.081e-02

Conversion electron

8.04290e-02

3.856e-01

Conversion electron

8.47290e-02

2.516e-01

Conversion electron

9.82501e-02

1.851e-01

Conversion electron

1.02800e-01

6.625e-02

Conversion electron

1.35978e-01

1.571e-02

Conversion electron

1.36729e-01

1.635e-01

Conversion electron

1.41029e-01

8.715e-02

Conversion electron

1.42750e-01

1.370e-02

Conversion electron

1.54550e-01

7.453e-02

Conversion electron

1.59100e-01

2.678e-02

Conversion electron

2.42729e-01

1.406e-02

Conversion electron

6.63350e-01

2.683e-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

 

 

 

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