Polonium

Polonium is a highly radioactive chemical element with atomic number 84. Marie and Pierre Curie discovered it in 1898 while studying uranium ores.

Polonium-210: A radioactive polonium isotope with a half-life of about 138 days that decays by emitting alpha particles. This isotope’s intense alpha emission makes it the best-known polonium isotope and a major source of its hazards.
Radioactive decay: The spontaneous transformation of unstable atomic nuclei into more stable configurations, with the release of radiation. Polonium’s radioactivity is a particular instance of this nuclear process.
Marie Curie: A physicist and chemist who pioneered research on radioactivity and discovered polonium and radium with Pierre Curie. She co-discovered polonium and named it for her homeland, Poland.
Polonium-beryllium neutron source: A neutron source that produces neutrons when alpha particles from polonium strike beryllium. Polonium-210 provided alpha particles for compact neutron sources used in research and industry.
Radiation poisoning: Illness or injury caused by exposure to ionizing radiation. Ingested polonium can deliver a severe internal radiation dose.
Polonium-209: A radioactive isotope of polonium with a half-life of roughly 125 years. Its comparatively long half-life distinguishes it from the short-lived isotopes found in nature.
Half-life: The time required for half the radioactive nuclei in a sample to decay. Different polonium isotopes persist for dramatically different lengths of time.
Pierre Curie: A French physicist whose research included magnetism, piezoelectricity, and radioactivity. He collaborated with Marie Curie in identifying polonium in 1898.
Radioisotope heater unit: A device that uses heat from radioactive decay to warm equipment or maintain operating temperatures. Polonium-210’s decay heat was used in early Soviet lunar surface devices.
Alexander Litvinenko: A former Russian intelligence officer who died in London in 2006 after polonium-210 poisoning. His death brought international attention to polonium’s use as a covert poison.

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