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Radionuclide Dosimetric Data Sheets
Fermium-257
Summary data
General
Classification
Isotope: Fm-257
Atomic number (Z): 100
Mass number (A): 257
Neutron number (N): 157
Radioactive decay
Decay modes: α, Spontaneus fission
Half-life: 100.5 [d]
Decay constant: 7.9826e-08 [1/s]
Daughters: Cf-253 (99.8%), SF (0.21%)
Radioactive daughters: Cf-253
Dosimetric constants
Mean alpha energy: 6.6128 [MeV]
Mean electron energy: 0.14709 [MeV]
Mean photon energy: 0.15209 [MeV]
Air kerma rate constant, Γ10: 1.562e-17 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 2.024e-17 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 1.083e-12 [Gy·kg/Bq·s]
Equilibrium dose constant for alphas, Δα: 1.059e-12
[Gy·kg/Bq·s]
Equilibrium dose constant for betas/electrons, Δβ-,β+,e-:
2.357e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 2.437e-14
[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/Fm-257 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/Fm-257 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/Fm-257 Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
7.45437e-05 |
1.793e+01 |
X-ray |
|
3.86001e-03 |
1.331e-01 |
X-ray |
|
1.31965e-02 |
1.961e-02 |
X-ray |
|
1.54368e-02 |
2.922e-02 |
X-ray |
|
1.56809e-02 |
2.564e-01 |
X-ray |
|
1.90028e-02 |
5.601e-02 |
X-ray |
|
1.96961e-02 |
4.059e-02 |
X-ray |
|
1.97994e-02 |
1.151e-02 |
X-ray |
|
2.07498e-02 |
1.488e-01 |
X-ray |
|
2.09431e-02 |
2.943e-02 |
X-ray |
|
2.42552e-02 |
3.556e-02 |
X-ray |
|
2.44371e-02 |
1.120e-02 |
X-ray |
|
6.16000e-02 |
1.447e-02 |
Gamma |
|
1.10388e-01 |
1.637e-01 |
X-ray |
|
1.15701e-01 |
2.533e-01 |
X-ray |
|
1.29279e-01 |
2.966e-02 |
X-ray |
|
1.30526e-01 |
5.860e-02 |
X-ray |
|
1.34357e-01 |
1.569e-02 |
X-ray |
|
1.79400e-01 |
8.682e-02 |
Gamma |
|
2.41000e-01 |
1.098e-01 |
Gamma |
|
1.26905e+00 |
1.295e-02 |
Delayed beta |
|
1.14358e-04 |
4.871e+00 |
Auger electron |
|
1.93280e-04 |
2.882e+00 |
Auger electron |
|
2.11782e-04 |
2.238e-02 |
Auger electron |
|
3.35166e-04 |
4.750e+00 |
Auger electron |
|
6.65559e-04 |
8.778e-01 |
Auger electron |
|
2.38712e-03 |
4.385e-01 |
Auger electron |
|
2.79291e-03 |
1.495e+00 |
Auger electron |
|
3.45501e-03 |
3.597e-01 |
Auger electron |
|
4.21028e-03 |
2.334e-02 |
Auger electron |
|
1.17673e-02 |
3.447e-01 |
Auger electron |
|
1.57810e-02 |
1.853e-01 |
Auger electron |
|
1.98536e-02 |
2.337e-02 |
Auger electron |
|
3.55530e-02 |
3.487e-01 |
Conversion electron |
|
3.63580e-02 |
1.275e-01 |
Conversion electron |
|
4.16710e-02 |
6.677e-02 |
Conversion electron |
|
4.37700e-02 |
4.079e-01 |
Conversion electron |
|
4.89530e-02 |
2.860e-02 |
Conversion electron |
|
5.41530e-02 |
2.323e-02 |
Conversion electron |
|
5.64962e-02 |
1.399e-01 |
Conversion electron |
|
6.16000e-02 |
5.221e-02 |
Conversion electron |
|
7.83530e-02 |
3.385e-02 |
Conversion electron |
|
1.05370e-01 |
1.472e-01 |
Conversion electron |
|
1.53353e-01 |
7.670e-02 |
Conversion electron |
|
1.54158e-01 |
2.504e-02 |
Conversion electron |
|
1.74296e-01 |
2.799e-02 |
Conversion electron |
|
1.79400e-01 |
1.046e-02 |
Conversion electron |
|
2.14953e-01 |
2.812e-02 |
Conversion electron |
|
2.15758e-01 |
1.550e-02 |
Conversion electron |
|
2.35896e-01 |
1.267e-02 |
Conversion electron |
|
6.44069e+00 |
1.971e-02 |
Alpha |
|
6.51965e+00 |
9.242e-01 |
Alpha |
|
6.62241e+00 |
1.182e-02 |
Alpha |
|
6.69625e+00 |
3.350e-02 |
Alpha |
|
1.01895e-01 |
1.971e-02 |
Alpha recoil |
|
1.03144e-01 |
9.242e-01 |
Alpha recoil |
|
1.04770e-01 |
1.182e-02 |
Alpha recoil |
|
1.05938e-01 |
3.350e-02 |
Alpha recoil |
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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