The MOISTSCAN microwave moisture analyser is designed to use low
level “non ionizing” microwave radiation for the determination of
total moisture within the product. The frequency range utilized by the
MOISTSCAN moisture analysers is from 500 MHz to 10 GHz. The microwave
power emitted from the lower antenna is approximately 0.1milliWatts (mW).
Equipment emitting microwave radiation must conform to the regulations
set out by the national authority, ARPANSA, or the Australian Radiation
and Nuclear Safety Authority. The applicable standard in this case is
the Australia and New Zealand Standard AS/NZS 2772.1
2002 Maximum Exposure Levels to Radiofrequency Fields - 3kHz to 300GHz,
Radiation Protection Series Publication No. 3.
At 500MHz: At 10GHz: E, Electric field (V/m rms) 68.6 137 H, Magnetic field (A/m rms) 0.182 0.364 P, Power Flux (W/m2) 12.5 50
The parameters listed above are the highest levels allowable (averaged
over a 6 minute period) for a device in a workplace. The most applicable
limit here is the Power Flux, P. The output from a MOISTSCAN MA-500 is
1.1mW/m2 or 0.0011W/m2 which is less than 10,000 times lower than what
is required at 500MHz. This radiation level only exists directly between
the two antennas and in almost all cases is inaccessible due to the
conveyor belt. Microwave radiation further than 1 metre from the
analyser is virtually undetectable.
As an example, microwave ovens are legally allowed to leak radiation of
up to 5 milliwatts/cm² (National Health and Medical Research Council
1985). During commissioning a Callidan engineer can demonstrate with a
simple microwave leakage monitor that the radiation levels around the
MOISTSCAN MA-500 are far less that what is legally required from a
commercial microwave oven.
