Nuclide reference

U-235 — Uranium-235

U-235 की half-life 703.8 million years है। मुख्य decay mode: α decay → Th-231 (100%)।

Identification

तत्व
Uranium (U)
Atomic number Z
92
Mass number A
235
State
Radioactive

Key quantities

Half-life
703.8 million years
विशिष्ट गतिविधि
79,980 Bq/g
Gamma constant Γ
—
परिवहन के लिए A1 / A2 (SSR-6)
असीमित / असीमित
D-value (НП-067-24)
0.00008 TBq

Decay modes

  • α decay → Th-231 — 100 %
  • spontaneous fission — 7.2e-9 %

Main gamma lines

Energy, keVYield, %
185.71557.2
16.596 (Th-231) · X-ray line25.04
13.2828 (Th-231) · X-ray line23.69
25.64 (Th-231)14.12
143.7610.96
84.214 (Th-231)6.6
163.335.08
205.3115.01
109.161.54
202.111.08

Includes daughter nuclides in equilibrium: Th-231 (yield per decay of U-235); the emitting nuclide is in brackets. Equilibrium is reached in about 7.4 d.

Alpha and beta particles

RadiationEnergy, keVYield, %
α4,397.855
4,366.117
4,214.75.7
4,596.45
β⁻, E max289.29 (Th-231)40
306.49 (Th-231)33
207.2 (Th-231)12.8
288.43 (Th-231)12

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.

Uranium-235 (U-235) — reference data

What is in the card

This card gathers the key data of radionuclide U-235 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 U-235 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.