title: Determination of the four natural Ra isotopes in thermal waters by gamma-ray spectrometry.
abstract: Our method for the simultaneous determination of the four natural Ra isotopes ((226)Ra, (228)Ra, (224)Ra and (223)Ra) in thermal waters involves a separation of Ra on a selective filter (3M EMPORE Radium Rad disk), and a single counting using a broad-energy HPGe detector (BE Ge manufactured by CANBERRA). The calculation of (223)Ra and (228)Ra activities requires interference and cascade summing corrections. The (226)Ra activities in CO(2)-rich thermal waters of the Lodève Basin (South of France) range from 530 to 2240mBq/l. The low ((228)Ra/(226)Ra) activity ratios (0.19-0.29) suggest that Ra is mostly derived from the aquifer carbonates. The short-lived (224)Ra and (223)Ra are probably added to the water through recoil or desorption processes from Th-enriched coatings on the fracture walls.
authors: Géosciences Montpellier, Université Montpellier 2 et CNRS, place Eugène Bataillon, 34095 Montpellier cedex 05, France. condomines@gm.univ-montp2.fr
authors: M
authors: M
authors: Condomines
authors: S
authors: S
authors: Rihs
authors: E
authors: E
authors: Lloret
authors: J L
authors: JL
authors: Seidel
mesh_terms: D000465:Algorithms; D001417:Background Radiation; D011834:Radiation Monitoring / Q000379:methods*; D011868:Radioisotopes / Q000032:analysis*; D011886:Radon / Q000032:analysis*; D013051:Spectrometry, Gamma / Q000379:methods*; D014867:Water / Q000737:chemistry*
chemical_list: D011868:Radioisotopes; D014867:Water; D011886:Radon