NRNDT Radio LU

Settings

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Calculator

Site zoning

On site the zone is sized on actual exposure time, not on continuous presence. The dose rate threshold is prorated between operation time and emission time.

Ci
min
Time on site with the source in place.
min
Cumulative time during which the source emits.
µSv/h
Working value for the public; replace it with your authorisation value.

Distance without collimator—m
With collimator
—
Prorated threshold
—
Dose constant K
—
Operation / emission ratio
—

Method

Ḣ_eff = Ḣ_allowed × t_operation / t_exposure

r = √(K / Ḣ_eff)

  • Ḣ_eff — prorated threshold in mSv/h (from the µSv/h value)
  • K — dose constant, A × 0.037 × Γ, in mSv·m²/h
  • r — barriering distance in m

Prorating assumes that a person staying at the boundary for the whole operation receives no more than they would at the permitted dose rate during the exposure time. It does not replace a dosimeter or survey meter measurement on site.

Indicative result — check it against your authorisation and your dosimetry.