Curie

The basic unit of radioactivity contained in 1 g of radium, i.e., 3.7 × 10¹⁰ disintegrations per second (dps). Most commonly, 1/1,000th, the millicurie (mCi) or the 1/1,000,000th the microcurie (μCi, 2.2 × 10⁶ disintegrations per minute [dpm]) are used in laboratory work. In most equipment only about half of the disintegrations are detectable and thus 1 μC corresponds to 1,000,000 counts per minute (cpm). Since the Ci unit defines the rate of disintegrations/time unit and the half-life of the different isotope may vary greatly depending on the species, the shorter half-life isotopes lose their isotopic atoms faster. 1 Becquerel = 2.7027 × 10⁻¹¹ Curie (≈ 27 picocuries). isotopes