Nuclide reference
U-235 — Uranium-235
The half-life of U-235 is 703.8 million years. Main decay mode: α decay to Th-231 (100%).
Identification
- Element
- Uranium (U)
- Atomic number Z
- 92
- Mass number A
- 235
- State
- Radioactive
Key quantities
- Half-life
- 703.8 million years
- Specific activity
- 79,980 Bq/g
- Gamma constant Γ
- —
- A1 / A2 for transport (SSR-6, НП-053-16)
- unlimited / unlimited
- D-value (НП-067-24)
- 0.00008 TBq
Decay modes
- α decay → Th-231 — 100 %
- spontaneous fission — 7.2e-9 %
Main gamma lines
| Energy, keV | Yield, % |
|---|---|
| 185.715 | 57.2 |
| 16.596 (Th-231) · X-ray line | 25.04 |
| 13.2828 (Th-231) · X-ray line | 23.69 |
| 25.64 (Th-231) | 14.12 |
| 143.76 | 10.96 |
| 84.214 (Th-231) | 6.6 |
| 163.33 | 5.08 |
| 205.311 | 5.01 |
| 109.16 | 1.54 |
| 202.11 | 1.08 |
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
| Radiation | Energy, keV | Yield, % |
|---|---|---|
| α | 4,397.8 | 55 |
| 4,366.1 | 17 | |
| 4,214.7 | 5.7 | |
| 4,596.4 | 5 | |
| β⁻, E max | 289.29 (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
Other isotopes of this element
Reference data vs computed valuesHalf-life, gamma lines and D-value are reference data (ENDF/B-VIII.0, НП-067-24).Gamma constant Γ is H*(10) at 1 m computed from ICRP-107 spectra (NIST µ_en/ρ, ICRP-74 Table A.21) including short-lived progeny in equilibrium (e.g. Cs-137/Ba-137m, Ra-226 series); specific activity uses molar mass M ≈ mass number A.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.