Caesium-137

Subject :Science and Technology

Context: A tiny radioactive capsule is lost on a highway in Western Australia.

More on the News:

It was discovered the truck had lost a rather special piece of cargo somewhere along the way: a tiny capsule containing a highly radioactive substance, used in a radiation gauge on the mine site.
Western Australia’s Department of Fire and Emergency Services are now searching for the missing ceramic capsule.

Caesium-137:

The capsule contains caesium-137, a radioactive isotope which spits out electrons (or beta radiation) and high-energy photons (or gamma radiation).
The beta radiation is blocked by the shell of the capsule, but the gamma radiation streams right through
The source has an activity of 19 gigabecquerels, which means it emits about 19 billion high-energy photons per second.
Caesium-137 is dangerous stuff, but the radiation it produces can also be very useful. It is used in some cancer treatments, for measuring the thickness of metal or the flow of liquids, and for calibrating radiation gauges.
Half life: Caesium-137 has a half-life of just over 30 years, which means the source’s radiation output will halve every 30 years, until it disappears completely.