Nuclide reference

Th-231 — Thorium-231

Th-231 की half-life 1.0633 d है। मुख्य decay mode: β⁻ decay → Pa-231 (100%)।

Identification

तत्व
Thorium (Th)
Atomic number Z
90
Mass number A
231
State
Radioactive

Key quantities

Half-life
1.0633 d
विशिष्ट गतिविधि
1.967e+16 Bq/g
Gamma constant Γ
—
परिवहन के लिए A1 / A2 (SSR-6)
40 TBq / 0.02 TBq
D-value (НП-067-24)
10 TBq

Decay modes

  • β⁻ decay → Pa-231 — 100 %

Main gamma lines

Energy, keVYield, %
16.596 · X-ray line25.04
13.2828 · X-ray line23.69
25.6414.12
84.2146.6
89.950.9966
81.2280.8976
58.570.462
102.270.4363
82.0870.4158
72.7510.2521

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

Alpha and beta particles

RadiationEnergy, keVYield, %
β⁻, E max289.2940
306.4933
207.212.8
288.4312

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.

Thorium-231 (Th-231) — reference data

What is in the card

This card gathers the key data of radionuclide Th-231 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 Th-231 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.