Summary data

General

Classification

Isotope: Po-208
Atomic number (Z): 84
Mass number (A): 208
Neutron number (N): 124

Radioactive decay

Decay modes: α, Electron capture
Half-life: 2.898 [y]
Decay constant: 7.5794e-09 [1/s]
Daughters: Bi-208 (0.00223%), Pb-204 (100.0%)
Radioactive daughters: Bi-208

Dosimetric constants

Mean alpha energy: 5.2153 [MeV]
Mean electron energy: 0.0 [MeV]
Mean photon energy: 2e-05 [MeV]
Air kerma rate constant, Γ₁₀: 1.475e-21 [Gy·m²/Bq·s]
Air kerma coefficient, K_air: 1.475e-21 [Gy·m²/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or electrons), Δ_wp: 8.356e-13 [Gy·kg/Bq·s]
Equilibrium dose constant for alphas, Δ_α: 8.356e-13 [Gy·kg/Bq·s]
Equilibrium dose constant for betas/electrons, Δ_β-,β+,e-: 0.000e+00 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δ_p: 3.204e-18 [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/Po-208 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/Po-208 Summary 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/Po-208 Summary Spectrum.csv

Energy [MeV]	Yield [#/nt] if > 0.01	Radiation type
5.11514e+00	1.000e+00	Alpha
1.00362e-01	1.000e+00	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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