Nuclide reference
Se-75 — Selenium-75
The half-life of Se-75 is 119.79 d. Main decay mode: electron capture to As-75 (100%).
Identification
- Element
- Selenium (Se)
- Atomic number Z
- 34
- Mass number A
- 75
- State
- Radioactive
Key quantities
- Half-life
- 119.79 d
- Specific activity
- 5.378e+14 Bq/g
- Gamma constant Γ (H*(10))
- 0.06619 µSv·m²/(MBq·h)
- Dose rate, 1 GBq at 1 m
- ≈ 66.2 µSv/h
- A1 / A2 for transport (SSR-6, НП-053-16)
- 3 TBq / 3 TBq
- D-value (НП-067-24)
- 0.2 TBq
Decay modes
- electron capture → As-75 — 100 %
Main gamma lines
| Energy, keV | Yield, % |
|---|---|
| 264.658 | 58.9 |
| 136 | 58.25 |
| 10.543 · X-ray line | 31.77 |
| 279.542 | 24.99 |
| 121.116 | 17.2 |
| 10.508 · X-ray line | 16.4 |
| 400.657 | 11.47 |
| 96.734 | 3.42 |
| 198.606 | 1.478 |
| 303.924 | 1.316 |
Lines of the bare nuclide (ENDF/B-VIII.0), without daughter ingrowth.
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 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.Dose rate example: point source, no shielding or scatter, Ḣ = Γ·A/r².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.