Nuclide reference

At-211 — Astatine-211

At-211 की half-life 7.214 h है। मुख्य decay mode: electron capture → Po-211 (58.2%)।

Identification

तत्व
Astatine (At)
Atomic number Z
85
Mass number A
211
State
Radioactive

Key quantities

Half-life
7.214 h
विशिष्ट गतिविधि
7.618e+16 Bq/g
Gamma constant Γ
—
परिवहन के लिए A1 / A2 (SSR-6)
20 TBq / 0.5 TBq
D-value (НП-067-24)
0.5 TBq

Decay modes

  • electron capture → Po-211 — 58.2 %
  • α decay → Bi-207 — 41.8 %

Main gamma lines

Energy, keVYield, %
79.291 · X-ray line21.18
76.864 · X-ray line12.68
897.8 (Po-211)0.3207
569.65 (Po-211)0.3114
6870.2606
669.780.003678
742.720.001045
892.40.0001421

Includes daughter nuclides in equilibrium: Po-211 (yield per decay of At-211); the emitting nuclide is in brackets. Equilibrium is reached in about 3.6 s.

Alpha and beta particles

RadiationEnergy, keVYield, %
α5,869.541.8
7,450.3 (Po-211)57.57
6,891.5 (Po-211)0.3178
6,568.3 (Po-211)0.3125

Related calculators

Reference data vs computed valuesHalf-life, gamma lines and D-value are reference data (ENDF/B-VIII.0, НП-067-24).Gamma constant Γ 1 m पर H*(10) है, ICRP-107 spectra (NIST µ_en/ρ, ICRP-74 Table A.21) से गणना की गई, equilibrium में short-lived progeny सहित (जैसे Cs-137/Ba-137m, Ra-226 series); specific activity molar mass M ≈ mass number A का उपयोग करती है।K-series X-ray energies are from NIST SRD 128 (Deslattes et al., 2003): in ENDF/B-VIII.0 they are given to 1 % and shifted by up to 0.7 keV for heavy elements. L-series lines and all yields are ENDF/B-VIII.0.

Astatine-211 (At-211) — reference data

What is in the card

This card gathers the key data of radionuclide At-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 At-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.