Curie

The curie (symbol Ci) is a non-SI unit of radioactivity, named 'in honour of' Pierre Curie, according to his widow, the famed radiation researcher Marie Curie, who was on the standards committee and perhaps a more likely candidate for the naming honors.

It was originally defined as "the quantity or mass of radium emanation in equilibrium with one gram of radium (element)" but is currently defined as: 1 Ci = 3.7 × 10¹⁰decays per second after more accurate measurements of the activity of ²²⁶Ra (which has a specific activity of 3.66 x 10¹⁰ Bq/g.)

In 1975 the General Conference on Weights and Measures gave the becquerel (Bq), equal to one reciprocal second, official status as the SI unit of activity. Therefore:

and

While its continued use is discouraged by NIST and other bodies, the curie is still widely used throughout the government, industry and medicine in the United States and in other countries.

The curie is a large amount of activity, and was intentionally so. According to Bertram Boltwood, Marie Curie thought that 'the use of the name "curie" for so infinitesimally small (a) quantity of anything was altogether inappropriate.'

Marie Curie

Marie Skłodowska Curie (/ˈkjʊri, kjʊˈriː/;French: [kyʁi]; Polish: [kʲiˈri]; 7 November 1867 – 4 July 1934), born Maria Salomea Skłodowska [ˈmarja salɔˈmɛa skwɔˈdɔfska], was a Polish and naturalized-French physicist and chemist who conducted pioneering research on radioactivity. She was the first woman to win a Nobel Prize, the first person and only woman to win twice, the only person to win twice in multiple sciences, and was part of the Curie family legacy of five Nobel Prizes. She was also the first woman to become a professor at the University of Paris, and in 1995 became the first woman to be entombed on her own merits in the Panthéon in Paris.

She was born in Warsaw, in what was then the Kingdom of Poland, part of the Russian Empire. She studied at Warsaw's clandestine Floating University and began her practical scientific training in Warsaw. In 1891, aged 24, she followed her older sister Bronisława to study in Paris, where she earned her higher degrees and conducted her subsequent scientific work. She shared the 1903 Nobel Prize in Physics with her husband Pierre Curie and with physicist Henri Becquerel. She won the 1911 Nobel Prize in Chemistry.