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Radionuclide Dosimetric Data Sheets
Francium-220
Summary data
General
Classification
Isotope: Fr-220
Atomic number (Z): 87
Mass number (A): 220
Neutron number (N): 133
Radioactive decay
Decay modes: α, β-
Half-life: 27.4 [s]
Decay constant: 2.5297e-02 [1/s]
Daughters: At-216 (99.7%), Ra-220 (0.35%)
Radioactive daughters: At-216, Ra-220
Dosimetric constants
Mean alpha energy: 6.7411 [MeV]
Mean electron energy: 0.01627 [MeV]
Mean photon energy: 0.01047 [MeV]
Air kerma rate constant, Γ10: 3.655e-18 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 3.655e-18 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 1.083e-12 [Gy·kg/Bq·s]
Equilibrium dose constant for alphas, Δα: 1.080e-12
[Gy·kg/Bq·s]
Equilibrium dose constant for betas/electrons, Δβ-,β+,e-:
2.607e-15 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 1.677e-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/Fr-220 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/Fr-220 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/Fr-220 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/Fr-220 Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
4.42764e-05 |
3.771e+00 |
X-ray |
|
2.62643e-03 |
1.666e-02 |
X-ray |
|
1.14288e-02 |
3.769e-02 |
X-ray |
|
1.39286e-02 |
2.119e-02 |
X-ray |
|
7.92282e-02 |
1.934e-02 |
X-ray |
|
8.18531e-02 |
3.205e-02 |
X-ray |
|
3.80386e-05 |
9.386e-01 |
Auger electron |
|
1.05627e-04 |
1.143e+00 |
Auger electron |
|
1.77112e-04 |
6.196e-01 |
Auger electron |
|
4.64356e-04 |
1.523e-01 |
Auger electron |
|
1.03614e-03 |
9.387e-02 |
Auger electron |
|
2.06606e-03 |
3.362e-01 |
Auger electron |
|
2.37778e-03 |
4.824e-02 |
Auger electron |
|
8.76096e-03 |
8.679e-02 |
Auger electron |
|
9.81200e-03 |
2.654e-02 |
Conversion electron |
|
1.14155e-02 |
4.032e-02 |
Auger electron |
|
2.71270e-02 |
1.003e-01 |
Conversion electron |
|
2.77600e-02 |
1.008e-02 |
Conversion electron |
|
4.12015e-02 |
2.637e-02 |
Conversion electron |
|
4.44600e-02 |
2.097e-02 |
Conversion electron |
|
4.70850e-02 |
1.883e-02 |
Conversion electron |
|
5.79015e-02 |
1.078e-02 |
Conversion electron |
|
6.46620e-02 |
1.023e-02 |
Conversion electron |
|
6.40383e+00 |
1.255e-02 |
Alpha |
|
6.47276e+00 |
1.305e-02 |
Alpha |
|
6.51917e+00 |
3.011e-02 |
Alpha |
|
6.52636e+00 |
2.509e-02 |
Alpha |
|
6.57301e+00 |
9.034e-02 |
Alpha |
|
6.62090e+00 |
1.606e-02 |
Alpha |
|
6.63319e+00 |
1.225e-01 |
Alpha |
|
6.67697e+00 |
6.625e-01 |
Alpha |
|
1.18667e-01 |
1.255e-02 |
Alpha recoil |
|
1.19944e-01 |
1.305e-02 |
Alpha recoil |
|
1.20804e-01 |
3.011e-02 |
Alpha recoil |
|
1.20937e-01 |
2.509e-02 |
Alpha recoil |
|
1.21802e-01 |
9.034e-02 |
Alpha recoil |
|
1.22689e-01 |
1.606e-02 |
Alpha recoil |
|
1.22917e-01 |
1.225e-01 |
Alpha recoil |
|
1.23728e-01 |
6.625e-01 |
Alpha recoil |
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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