Marie Curie was present in such minute quantities that they would eventually have to process tons of the ore. In July 1898, Curie and her husband published a joint paper announcing the existence of an element which they named "polonium", in honour of her native Poland, which would for another twenty years remain partitioned among three empires (Russian, Austrian, and Prussian). On 26 December 1898, the Curies announced the existence of a second element, which they named "radium", from the Latin word for "ray". In the course of their research, they also coined the word "radioactivity". To prove their discoveries beyond any
Polonium coolant. The longer-lived isotopes of polonium, Po and Po, can be formed by proton or deuteron bombardment of bismuth using a cyclotron. Other more neutron-rich and more unstable isotopes can be formed by the irradiation of platinum with carbon nuclei. Polonium-based sources of alpha particles were produced in the former Soviet Union. Such sources were applied for measuring the thickness of industrial coatings via attenuation of alpha radiation. Because of intense alpha radiation, a one-gram sample of Po will spontaneously heat up to above generating about 140 watts of power. Therefore, Po is used as an atomic heat source to