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Radionuclide Dosimetric Data Sheets
Krypton-81
Summary data
General
Classification
Isotope: Kr-81
Atomic number (Z): 36
Mass number (A): 81
Neutron number (N): 45
Radioactive decay
Decay modes: Electron capture
Half-life: 229000.0 [y]
Decay constant: 9.5917e-14 [1/s]
Daughters: Br-81 (100.0%)
Radioactive daughters: None
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 0.00518 [MeV]
Mean photon energy: 0.00719 [MeV]
Air kerma rate constant, Γ10: 2.118e-17 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 2.118e-17 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 8.299e-16 [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-:
8.299e-16 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 1.152e-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/Kr-81 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/Kr-81 Summary 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/Kr-81 Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
1.75899e-05 |
7.128e+00 |
X-ray |
|
1.47515e-03 |
1.077e-02 |
X-ray |
|
1.18329e-02 |
1.534e-01 |
X-ray |
|
1.18814e-02 |
2.963e-01 |
X-ray |
|
1.32432e-02 |
2.116e-02 |
X-ray |
|
1.32502e-02 |
4.129e-02 |
X-ray |
|
4.38687e-05 |
3.207e+00 |
Auger electron |
|
5.77605e-05 |
1.243e+00 |
Auger electron |
|
9.13731e-05 |
2.307e-01 |
Auger electron |
|
1.32099e-03 |
1.059e+00 |
Auger electron |
|
1.41223e-03 |
6.293e-02 |
Auger electron |
|
1.02029e-02 |
2.455e-01 |
Auger electron |
|
1.16354e-02 |
7.509e-02 |
Auger 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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