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Radionuclide Dosimetric Data Sheets

Polonium-212m

Isotope:  Po-212m
Atomic number (Z):  84
Mass number (A):  212
Neutron number (N):  128

Decay modes:  α
Half-life:  45.1 [s]
Decay constant:  1.5369e-02 [1/s]
Daughters:  Pb-208 (99.9%)
Radioactive daughters:  None

Mean alpha energy:  11.775 [MeV]
Mean electron energy:  0.00036 [MeV]
Mean photon energy:  0.07923 [MeV]
Air kerma rate constant, Γ₁₀:  2.315e-18 [Gy·m²/Bq·s]
Air kerma coefficient, K_air:  2.315e-18 [Gy·m²/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or electrons), Δ_wp:  1.887e-12 [Gy·kg/Bq·s]
Equilibrium dose constant for alphas, Δ_α:  1.887e-12 [Gy·kg/Bq·s]
Equilibrium dose constant for betas/electrons, Δ_β-,β+,e-:  5.768e-17 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δ_p:  1.269e-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/Po-212m 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/Po-212m 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/Po-212m Summary Spectrum.csv

 

Energy [MeV]	Yield [#/nt] if > 0.01	Radiation type
5.70000e-01	1.999e-02	Gamma
2.61000e+00	2.598e-02	Gamma
8.52138e+00	2.050e-02	Alpha
1.16512e+01	9.688e-01	Alpha
1.63979e-01	2.050e-02	Alpha recoil
2.24206e-01	9.688e-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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