Nuclide reference
Am-243 — Americium-243
The half-life of Am-243 is 7,370 years. Main decay mode: α decay to Np-239 (100%).
Identification
- Element
- Americium (Am)
- Atomic number Z
- 95
- Mass number A
- 243
- State
- Radioactive
Key quantities
- Half-life
- 7,370 years
- Specific activity
- 7.386e+9 Bq/g
- Gamma constant Γ
- —
- A1 / A2 for transport (SSR-6, НП-053-16)
- 5 TBq / 0.001 TBq
- D-value (НП-067-24)
- 0.2 TBq
Decay modes
- α decay → Np-239 — 100 %
- spontaneous fission — 3.7e-9 %
Main gamma lines
| Energy, keV | Yield, % |
|---|---|
| 74.66 | 67.2 |
| 106.123 (Np-239) | 26.3 |
| 14.2745 (Np-239) · X-ray line | 22.33 |
| 103.735 (Np-239) · X-ray line | 21.58 |
| 277.599 (Np-239) | 14.44 |
| 228.183 (Np-239) | 11.14 |
| 43.53 | 5.9 |
| 209.753 (Np-239) | 3.42 |
| 4.2 (Np-239) | 2.7 |
| 334.31 (Np-239) | 2.06 |
Includes daughter nuclides in equilibrium: Np-239 (yield per decay of Am-243); the emitting nuclide is in brackets. Equilibrium is reached in about 16 d.
Alpha and beta particles
| Radiation | Energy, keV | Yield, % |
|---|---|---|
| α | 5,275.3 | 87.1 |
| 5,233.3 | 11.2 | |
| 5,181 | 1.36 | |
| 5,321 | 0.16 | |
| β⁻, E max | 436.34 (Np-239) | 45 |
| 330.21 (Np-239) | 42 | |
| 391.68 (Np-239) | 7 | |
| 713.94 (Np-239) | 2 |
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.