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Radionuclide Dosimetric Data Sheets
Cobalt-55
Summary data
General
Classification
Isotope: Co-55
Atomic number (Z): 27
Mass number (A): 55
Neutron number (N): 28
Radioactive decay
Decay modes: β+, Electron capture
Half-life: 17.53 [h]
Decay constant: 1.0984e-05 [1/s]
Daughters: Fe-55 (100.0%)
Radioactive daughters: Fe-55
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 0.43119 [MeV]
Mean photon energy: 1.99597 [MeV]
Air kerma rate constant, Γ10: 4.306e-17 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 7.242e-17 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 6.908e-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-:
6.908e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 3.198e-13
[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/Co-55 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/Co-55 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/Co-55 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/Co-55 Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
1.25308e-05 |
1.389e+00 |
X-ray |
|
6.34985e-03 |
2.182e-02 |
X-ray |
|
6.36272e-03 |
4.274e-02 |
X-ray |
|
9.19000e-02 |
1.162e-02 |
Gamma |
|
4.11500e-01 |
1.073e-02 |
Gamma |
|
4.77200e-01 |
2.018e-01 |
Gamma |
|
5.11000e-01 |
1.517e+00 |
Annihilation photon |
|
8.03700e-01 |
1.868e-02 |
Gamma |
|
9.31100e-01 |
7.500e-01 |
Gamma |
|
1.31660e+00 |
7.087e-02 |
Gamma |
|
1.37000e+00 |
2.917e-02 |
Gamma |
|
1.40850e+00 |
1.688e-01 |
Gamma |
|
4.35589e-01 |
2.564e-01 |
Positron |
|
4.76131e-01 |
4.290e-02 |
Positron |
|
6.48717e-01 |
4.589e-01 |
Positron |
|
4.00282e-05 |
5.973e-01 |
Auger electron |
|
6.97184e-05 |
6.568e-02 |
Auger electron |
|
6.26750e-04 |
3.359e-01 |
Auger electron |
|
5.58186e-03 |
1.134e-01 |
Auger electron |
|
6.25798e-03 |
2.774e-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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