Gamma Boundary Calculator

Estimate the radius where dose rate drops below a selected threshold using a point-source inverse-square approximation. Select a source, enter activity, then place a pin on the map to preview the boundary area.

Gamma source

Source strength

Strength unit

Threshold boundary limit

uSv/h

Source notes (optional)

Boundary radius:

- m

Diameter:

- m

Preset gamma constant:

- uSv m^2/(GBq h)

Calculation basis: dose rate = Gamma Constant x Activity / distance^2. Values are indicative and conservative checks are still required.

Map boundary preview

Click the map to place/move the source pin. The boundary circle updates automatically from your inputs.

Loading map...

Safety notice. Informational use only. This calculator does not replace local rules, radiation surveys, calibrated instruments, supervised area setup, or competent radiation protection decisions. Always perform manual checks and verification before work.

Disclaimer. This tool is for education and reference only. It does not replace qualified health physics advice, workplace procedures, or regulatory compliance. Full disclaimer