Curium

Curium is a radioactive, silvery metal in the actinide family. It does not occur in natural deposits; only tiny traces can form in uranium ores through nuclear reactions. Curium is made in nuclear reactors by exposing uranium or plutonium to neutrons, and it can be recovered in small amounts from spent nuclear fuel. Its intense radioactivity and scarcity limit its uses. Curium isotopes have been used in scientific research and to produce other radioactive materials. In particular, curium-244 served as a source of alpha particles in instruments that analyzed the surfaces of Mars rovers and a comet lander.