Nuclide reference
K-40 — Potassium-40
K-40 की half-life 1.248 billion years है। मुख्य decay mode: β⁻ decay → Ca-40 (89.14%)।
Identification
- तत्व
- Potassium (K)
- Atomic number Z
- 19
- Mass number A
- 40
- State
- Radioactive
Key quantities
- Half-life
- 1.248 billion years
- विशिष्ट गतिविधि
- 265,000 Bq/g
- Gamma constant Γ (H*(10))
- 0.02123 µSv·m²/(MBq·h)
- Dose rate, 1 GBq at 1 m
- ≈ 21.2 µSv/h
- परिवहन के लिए A1 / A2 (SSR-6)
- 0.9 TBq / 0.9 TBq
- D-value (НП-067-24)
- —
Decay modes
- β⁻ decay → Ca-40 — 89.14 %
- β⁺ decay / electron capture → Ar-40 — 10.86 %
Main gamma lines
| Energy, keV | Yield, % |
|---|---|
| 1,460.82 | 10.66 |
| 2.955 · X-ray line | 0.9791 |
| 510.999 · annihilation 511 keV | 0.002 |
Lines of the bare nuclide (ENDF/B-VIII.0), without daughter ingrowth.
Alpha and beta particles
| Radiation | Energy, keV | Yield, % |
|---|---|---|
| β⁻, E max | 1,311.1 | 89.14 |
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।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.