В википедии в статье про полоний уже упоминается про Литвиненко:
Applications
When it is mixed or alloyed with beryllium, polonium can be a neutron source. Other uses;
- This element has also been used in devices that eliminate static charges in textile mills and other places. However, beta sources are more commonly used and are less dangerous.
- Polonium is used on brushes that remove accumulated dust from photographic films. The polonium in these brushes is sealed and controlled thus minimizing radiation hazards.
- There is now at least one confirmed case of Polonium 210 being used as a poison (see below)
[edit] Polonium-210
This isotope of polonium is an alpha emitter that has a half-life of 138.39 days. A milligram of polonium-210 emits as many alpha particles as 5 grams of radium. A great deal of energy is released by its decay with a half a gram quickly reaching a temperature above 750 K. A few curies (gigabecquerels) of polonium-210 emit a blue glow which is caused by excitation of surrounding air. A single gram of polonium-210 generates 140 watts of heat energy. Since nearly all alpha radiation can be easily stopped by ordinary containers and upon hitting its surface releases its energy, polonium-210 has been used as a lightweight heat source to power thermoelectric cells in artificial satellites. A polonium-210 heat source was also used in each of the Lunokhod rovers deployed on the surface of the Moon, to keep their internal components warm during the lunar nights.
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Police are investigating the substance in connection with the death of former Russian spy Alexander Litvinenko in London in November 2006.
http://en.wikipedia.org/wiki/Polonium