Nuclide reference
Ra-225 — Radium-225
The half-life of Ra-225 is 14.9 d. Main decay mode: β⁻ decay to Ac-225 (100%).
Identification
- Element
- Radium (Ra)
- Atomic number Z
- 88
- Mass number A
- 225
- State
- Radioactive
Key quantities
- Half-life
- 14.9 d
- Specific activity
- 1.441e+15 Bq/g
- Gamma constant Γ
- —
- A1 / A2 for transport (SSR-6, НП-053-16)
- 0.2 TBq / 0.004 TBq
- D-value (НП-067-24)
- 0.1 TBq
Decay modes
- β⁻ decay → Ac-225 — 100 %
Main gamma lines
| Energy, keV | Yield, % |
|---|---|
| 40 | 30 |
| 15.636 · X-ray line | 5.788 |
| 12.6432 · X-ray line | 5.471 |
Lines of the bare nuclide (ENDF/B-VIII.0), without daughter ingrowth.
Alpha and beta particles
| Radiation | Energy, keV | Yield, % |
|---|---|---|
| β⁻, E max | 316.91 | 69.5 |
| 357 | 30.5 |
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.