सभी tools

Nuclide reference

At-218 — Astatine-218

At-218 की half-life 1.5 s है। मुख्य decay mode: α decay → Bi-214 (99.9%)।

Identification

तत्व
Astatine (At)
Atomic number Z
85
Mass number A
218
State
Radioactive

Key quantities

Half-life
1.5 s
विशिष्ट गतिविधि
1.277e+21 Bq/g
Gamma constant Γ
—
D-value (НП-067-24)
—

Decay modes

  • α decay → Bi-214 — 99.9 %
  • β⁻ decay → Rn-218 — 0.1 %

Main gamma lines

Energy, keVYield, %
62.6989.91

Lines of the nuclide itself (ENDF/B-VIII.0).

Alpha and beta particles

RadiationEnergy, keVYield, %
α6,69389.91
6,6536.394
6,7563.596
7,686.8 (Po-214)0.1024
β⁻, E max2,8810.1

For β⁻ the endpoint (maximum) energy of the spectrum is given. ENDF/B-VIII.0. Includes daughter nuclides in equilibrium: Po-214 (yield per decay of At-218); the emitting nuclide is in brackets. Equilibrium is reached in about 0.25 s.

Related calculators

Decayगतिविधि ↔ द्रव्यमानDose rate

इसी element के अन्य isotopes

At-211
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।

Astatine-218 (At-218) — reference data

What is in the card

This card gathers the key data of radionuclide At-218 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-218 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.