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Radionuclide Dosimetric Data Sheets

Cobalt-61

Isotope:  Co-61
Atomic number (Z):  27
Mass number (A):  61
Neutron number (N):  34

Decay modes:  β-
Half-life:  1.65 [h]
Decay constant:  1.1669e-04 [1/s]
Daughters:  Ni-61 (100.0%)
Radioactive daughters:  None

Mean alpha energy:  0.0 [MeV]
Mean electron energy:  0.46642 [MeV]
Mean photon energy:  0.09696 [MeV]
Air kerma rate constant, Γ₁₀:  3.427e-18 [Gy·m²/Bq·s]
Air kerma coefficient, K_air:  3.427e-18 [Gy·m²/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or electrons), Δ_wp:  7.473e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for alphas, Δ_α:  0.000e+00 [Gy·kg/Bq·s]
Equilibrium dose constant for betas/electrons, Δ_β-,β+,e-:  7.473e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δ_p:  1.553e-14 [Gy·kg/Bq·s]

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-61 DPK.csv

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-61 Summary Spectrum.csv

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-61 Beta Spectrum.csv

 

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-61 Summary Spectrum.csv

 

Energy [MeV]	Yield [#/nt] if > 0.01	Radiation type
1.45029e-05	5.962e-01	X-ray
7.41782e-03	1.262e-02	X-ray
7.43578e-03	2.465e-02	X-ray
6.74150e-02	8.467e-01	Gamma
9.09200e-01	3.616e-02	Gamma
1.29199e-01	4.400e-02	Beta
4.74159e-01	9.560e-01	Beta
4.79801e-05	2.317e-01	Auger electron
7.87860e-05	2.917e-02	Auger electron
7.72625e-04	1.562e-01	Auger electron
6.49788e-03	4.928e-02	Auger electron
7.31362e-03	1.232e-02	Auger electron
5.91122e-02	1.043e-01	Conversion electron
6.64085e-02	1.026e-02	Conversion electron

 

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

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

 

 

 

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