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Radionuclide Dosimetric Data Sheets

Radium-222

Isotope:  Ra-222
Atomic number (Z):  88
Mass number (A):  222
Neutron number (N):  134

Decay modes:  α
Half-life:  38.0 [s]
Decay constant:  1.8241e-02 [1/s]
Daughters:  Rn-218 (100.0%)
Radioactive daughters:  Rn-218

Mean alpha energy:  6.671 [MeV]
Mean electron energy:  0.00085 [MeV]
Mean photon energy:  0.00919 [MeV]
Air kerma rate constant, Γ₁₀:  3.749e-19 [Gy·m²/Bq·s]
Air kerma coefficient, K_air:  3.749e-19 [Gy·m²/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or electrons), Δ_wp:  1.069e-12 [Gy·kg/Bq·s]
Equilibrium dose constant for alphas, Δ_α:  1.069e-12 [Gy·kg/Bq·s]
Equilibrium dose constant for betas/electrons, Δ_β-,β+,e-:  1.362e-16 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δ_p:  1.472e-15 [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/Ra-222 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/Ra-222 Summary 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/Ra-222 Summary Spectrum.csv

 

Energy [MeV]	Yield [#/nt] if > 0.01	Radiation type
5.01027e-05	3.464e-02	X-ray
3.24220e-01	2.770e-02	Gamma
1.13311e-04	1.022e-02	Auger electron
6.24217e+00	3.051e-02	Alpha
6.56054e+00	9.694e-01	Alpha
1.14610e-01	3.051e-02	Alpha recoil
1.20455e-01	9.694e-01	Alpha recoil

 

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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