Nuclide reference

Ac-226 — Actinium-226

Ac-226 की half-life 1.2238 d है। मुख्य decay mode: β⁻ decay → Th-226 (83%)।

Identification

तत्व
Actinium (Ac)
Atomic number Z
89
Mass number A
226
State
Radioactive

Key quantities

Half-life
1.2238 d
विशिष्ट गतिविधि
1.747e+16 Bq/g
Gamma constant Γ
—
D-value (НП-067-24)
—

Decay modes

  • β⁻ decay → Th-226 — 83 %
  • electron capture → Ra-226 — 17 %
  • α decay → Fr-222 — 0.006 %

Main gamma lines

Energy, keVYield, %
23026.89
158.0517.48
16.1429 · X-ray line6.321
88.4734 · X-ray line5.947
253.55.716
185.64.763
111.12 (Th-226)2.779
324.31 (Ra-222)2.341
242.12 (Th-226)0.7314
72.230.5647

Includes daughter nuclides in equilibrium: Th-226, Ra-222, Rn-218, Po-214 (yield per decay of Ac-226); the emitting nuclide is in brackets. Equilibrium is reached in about 3.6 h. Equilibrium with radon requires a sealed source.

Alpha and beta particles

RadiationEnergy, keVYield, %
α6,336.8 (Th-226)63.77
6,559 (Ra-222)81.88
7,129.2 (Rn-218)84.39
7,686.8 (Po-214)84.49
β⁻, E max882.6349
1,11324
1,040.810
265.20.092

For β⁻ the endpoint (maximum) energy of the spectrum is given. ENDF/B-VIII.0.

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.

Actinium-226 (Ac-226) — reference data

What is in the card

This card gathers the key data of radionuclide Ac-226 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 Ac-226 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.