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Nuclide reference

Po-211 — Polonium-211

The half-life of Po-211 is 516 ms. Main decay mode: α decay to Pb-207 (100%).

Identification

Element
Polonium (Po)
Atomic number Z
84
Mass number A
211
State
Radioactive

Key quantities

Half-life
516 ms
Specific activity
3.834e+21 Bq/g
Gamma constant Γ
—
D-value (НП-067-24)
—

Decay modes

  • α decay → Pb-207 — 100 %

Main gamma lines

Energy, keVYield, %
897.80.551
569.650.535
328.20.00321
1,063.660.0007223

Lines of the bare nuclide (ENDF/B-VIII.0), without daughter ingrowth.

Alpha and beta particles

RadiationEnergy, keVYield, %
α7,450.398.92
6,891.50.546
6,568.30.537

Related calculators

DecayActivity ↔ massDose rate

Other isotopes of this element

Po-210
Reference data vs computed valuesHalf-life, gamma lines and D-value are reference data (ENDF/B-VIII.0, НП-067-24).Gamma constant Γ is H*(10) at 1 m computed from ICRP-107 spectra (NIST µ_en/ρ, ICRP-74 Table A.21) including short-lived progeny in equilibrium (e.g. Cs-137/Ba-137m, Ra-226 series); specific activity uses molar mass M ≈ mass number A.

Polonium-211 (Po-211) — reference data

What is in the card

This card gathers the key data of radionuclide Po-211 in one place: half-life, decay modes, main gamma lines, alpha and beta particle energies, gamma constant, specific activity and the D-value for source categorization. Decay and emission data are from ENDF/B-VIII.0; the D-value follows NP-067-24; the gamma constant is the ambient dose equivalent H*(10) at 1 m, computed from ICRP-107 spectra.

How to use the data

Half-life and specific activity let you recalculate the activity of a Po-211 source to the delivery or disposal date — use the decay calculator. Gamma lines with yields identify the nuclide from a spectrum and pick the line for gamma spectrometry; the gamma constant Γ gives the dose rate at a distance, while the D-value and A1/A2 set the source category and the package type for transport.