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Nuclide reference

Os-185 — Osmium-185

The half-life of Os-185 is 93.6 d. Main decay mode: electron capture to Re-185 (100%).

Identification

Element
Osmium (Os)
Atomic number Z
76
Mass number A
185
State
Radioactive

Key quantities

Half-life
93.6 d
Specific activity
2.79e+14 Bq/g
Gamma constant Γ
—
A1 / A2 for transport (SSR-6, НП-053-16)
1 TBq / 1 TBq
D-value (НП-067-24)
0.1 TBq

Decay modes

  • electron capture → Re-185 — 100 %

Main gamma lines

Energy, keVYield, %
646.11678
61.141 · X-ray line35.02
59.718 · X-ray line20.25
874.8136.295
880.5235.171
717.4243.939
592.0741.318
162.8520.5663
234.1570.4126
125.3580.3416

Lines of the bare nuclide (ENDF/B-VIII.0), without daughter ingrowth.

Related calculators

DecayActivity ↔ massSource categoryDose rateA1/A2 and package type
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.

Osmium-185 (Os-185) — reference data

What is in the card

This card gathers the key data of radionuclide Os-185 in one place: half-life, decay modes, main gamma lines, alpha and beta particle energies, gamma constant, specific activity and the D-value for source categorization. Decay and emission data are from ENDF/B-VIII.0; the D-value follows NP-067-24; the gamma constant is the ambient dose equivalent H*(10) at 1 m, computed from ICRP-107 spectra.

How to use the data

Half-life and specific activity let you recalculate the activity of a Os-185 source to the delivery or disposal date — use the decay calculator. Gamma lines with yields identify the nuclide from a spectrum and pick the line for gamma spectrometry; the gamma constant Γ gives the dose rate at a distance, while the D-value and A1/A2 set the source category and the package type for transport.