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Specific activity (symbol a) is the activity per unit mass of a radionuclide and is a physical property of that radionuclide. [ 1 ] [ 2 ] It is usually given in units of becquerel per kilogram (Bq/kg), but another commonly used unit of specific activity is the curie per gram (Ci/g).
Several of these workers died from illnesses caused by radium exposure. [5] Many rocks and soils contain low concentrations of 226 Ra, which forms from the radioactive decay of naturally occurring uranium. The decay of 226 Ra produces radon-222, a radioactive gas that can accumulate in inadequately ventilated homes and other enclosed spaces.
It was originally defined as "the quantity or mass of radium emanation in equilibrium with one gram of radium (element)", [1] but is currently defined as 1 Ci = 3.7 × 10 10 decays per second [4] after more accurate measurements of the activity of 226 Ra (which has a specific activity of 3.66 × 10 10 Bq/g [5]).
It consisted of triple-distilled water containing at a minimum 1 microcurie (37 kBq) each of the radium-226 and 228 isotopes. The time of Radithor and radioactive elixirs ended in 1932, with the premature death of one of its most fervent users, Eben Byers, an American golfer. This history led to the strengthening of regulatory control of ...
Because of its relative longevity, 226 Ra is the most common isotope of the element, making up about one part per trillion of the Earth's crust; essentially all natural radium is 226 Ra. [29] Thus, radium is found in tiny quantities in the uranium ore uraninite and various other uranium minerals, and in even tinier quantities in thorium minerals.
Radium (88 Ra) has no stable or nearly stable isotopes, and thus a standard atomic weight cannot be given. The longest lived, and most common, isotope of radium is 226 Ra with a half-life of 1600 years. 226 Ra occurs in the decay chain of 238 U (often referred to as the radium series). Radium has 34 known isotopes from 201 Ra to 234 Ra.
228 Ra № 4–6 a: 155 Eu þ: 248 Bk [3] > 9 a: 244 Cm ƒ: 241 Pu ƒ: 250 Cf 227 Ac № 10–29 a: 90 Sr 85 Kr 113m Cd þ: 232 U ƒ: 238 Pu ƒ: 243 Cm ƒ: 29–97 a: 137 Cs 151 Sm þ: 121m Sn 249 Cf ƒ: 242m Am ƒ: 141–351 a No fission products have a half-life in the range of 100 a–210 ka ... 241 Am ƒ: 251 Cf ƒ [4] 430–900 a 226 Ra ...
All EU countries are required to ensure that the activity concentrations of radium-226, thorium-232 and potassium-40 in construction products which be of concern from a radiation protection point of view, are determined and the resulting radiation exposure assessed before they are placed on the market.