Environmental gamma radiation is continuously measured by dosimeters around the Lucas Heights site and in the local area. Environmental radiation levels are also monitored at a station in Engadine; the data is published online every 15 minutes.
The annual detector calibration check is planned for Wednesday 6 December which will cause a spike in the Environmental Radiation data.
Engadine's local radiation and rainfall levels
Engadine's previous radiation levels
Daily average for the last 30 days
Monthly average over the last year
Gamma radiation is a penetrating form of short wavelength electromagnetic radiation, similar to X-rays.
The environmental radiation graph (above) shows measurements in nanoGrays (nGy) which are units of absorbed radiation dose commonly used in environmental monitoring. A nanoGray is one billionth (one thousand millionth) of a Gray.
A temporary rise in environmental gamma radiation is often detected when it rains. This occurs because rain affects the behaviour of naturally occurring radionuclides, such as the gas radon. These radionuclides can be absorbed by raindrops and temporarily concentrated near the ground. Also, radon naturally builds up in air spaces in the soil and can be released when rain soaks into the ground.
"Spikes" in the environmental radiation graph (above) may occur during the regular calibration checks of the instrument that is needed to ensure accurate data. Gaps appearing in either graph are usually associated with delayed radio transmission of data from Engadine.