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Radionuclide Dosimetric Data Sheets
Einsteinium-256
Summary data
General
Classification
Isotope: Es-256
Atomic number (Z): 99
Mass number (A): 256
Neutron number (N): 157
Radioactive decay
Decay modes: β-
Half-life: 25.4 [m]
Decay constant: 4.5482e-04 [1/s]
Daughters: Fm-256 (100.0%)
Radioactive daughters: Fm-256
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 0.5822 [MeV]
Mean photon energy: 0.00315 [MeV]
Air kerma rate constant, Γ10: 2.117e-18 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 2.117e-18 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 9.328e-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-:
9.328e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 5.047e-16
[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/Es-256 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/Es-256 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/Es-256 Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
7.64760e-05 |
3.026e+00 |
X-ray |
|
4.08923e-03 |
2.441e-02 |
X-ray |
|
1.64013e-02 |
4.429e-02 |
X-ray |
|
2.20312e-02 |
5.332e-02 |
X-ray |
|
2.57302e-02 |
1.296e-02 |
X-ray |
|
5.56969e-01 |
3.300e-01 |
Beta |
|
5.75432e-01 |
6.700e-01 |
Beta |
|
1.27977e-04 |
7.919e-01 |
Auger electron |
|
1.91315e-04 |
4.929e-01 |
Auger electron |
|
3.92863e-04 |
8.046e-01 |
Auger electron |
|
7.02712e-04 |
1.478e-01 |
Auger electron |
|
2.39997e-03 |
2.895e-02 |
Auger electron |
|
2.92392e-03 |
2.528e-01 |
Auger electron |
|
3.65343e-03 |
6.565e-02 |
Auger electron |
|
1.24025e-02 |
5.929e-02 |
Auger electron |
|
1.66605e-02 |
3.245e-02 |
Auger electron |
|
2.15080e-02 |
1.302e-01 |
Conversion electron |
|
2.74060e-02 |
1.002e-01 |
Conversion electron |
|
4.29074e-02 |
6.817e-02 |
Conversion electron |
|
4.83000e-02 |
2.552e-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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