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Radionuclide Dosimetric Data Sheets
Krypton-81m
Summary data
General
Classification
Isotope: Kr-81m
Atomic number (Z): 36
Mass number (A): 81
Neutron number (N): 45
Radioactive decay
Decay modes: Electron capture, Internal transition
Half-life: 13.1 [s]
Decay constant: 5.2912e-02 [1/s]
Daughters: Kr-81 (100.0%), Br-81 (0.0025%)
Radioactive daughters: Kr-81
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 0.0596 [MeV]
Mean photon energy: 0.13085 [MeV]
Air kerma rate constant, Γ10: 1.053e-17 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 1.053e-17 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 9.549e-15 [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-:
9.549e-15 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 2.096e-14
[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-81m 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-81m 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-81m Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
1.93791e-05 |
2.153e+00 |
X-ray |
|
1.25517e-02 |
5.083e-02 |
X-ray |
|
1.26066e-02 |
9.802e-02 |
X-ray |
|
1.40730e-02 |
1.395e-02 |
X-ray |
|
1.90460e-01 |
6.752e-01 |
Gamma |
|
5.62585e-05 |
9.420e-01 |
Auger electron |
|
6.54780e-05 |
3.698e-01 |
Auger electron |
|
9.82524e-05 |
6.400e-02 |
Auger electron |
|
1.40715e-03 |
3.312e-01 |
Auger electron |
|
1.51159e-03 |
2.391e-02 |
Auger electron |
|
1.07980e-02 |
7.249e-02 |
Auger electron |
|
1.23371e-02 |
2.301e-02 |
Auger electron |
|
1.76180e-01 |
2.691e-01 |
Conversion electron |
|
1.88558e-01 |
2.552e-02 |
Conversion electron |
|
1.88732e-01 |
1.065e-02 |
Conversion electron |
|
1.88787e-01 |
1.082e-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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