A radioisotope thermoelectric generator (RTG, RITEG), sometimes referred to as a radioisotope power system (RPS), is a type of that uses an array of to convert the of a suitable material into by the. This type of has no moving parts and is ideal for deployment in remote and harsh environ. Non-thermal converters extract energy from emitted radiation before it is degraded into heat. Unlike thermoelectric and thermionic converters their output does not depend on the temperature difference. Non-thermal generators can be classified by the type of particle used and by the mechanism by which their energy is converted. Energy can be extracted from emitted when their builds up in a,.