Low radioactivity portable coal face ash analyser

A coal face ash analyser based on gamma-gamma technique has been developed and tested at two coal mines. It is light in weight (2 kg) and uses two very low activity sources which ensure safe operation of this hand-held radiation instrument. The primary source of radiation is a 1.8 MBq 133Ba gamma-ray source. Another 0.35 MBq 137Cs gamma-ray source is used for gain stabilization. At field tests at a Queensland coal mine, ash in the range 7–23% ash was determined with a root mean square deviation of 2.6%. At a New South Wales coal mine, ash in the range 4–31% was determined to 3.3%.