Author/Authors :
Aharmim، نويسنده , , B. and Cleveland، نويسنده , , B.T and Dai، نويسنده , , X. and Doucas، نويسنده , , G. and Farine، نويسنده , , J. and Fergani، نويسنده , , H. L. Ford-Dunn، نويسنده , , R. and Hahn، نويسنده , , R.L and Hallman، نويسنده , , E.D. and Jelley، نويسنده , , N.A. and Lange، نويسنده , , R. and Majerus، نويسنده , , S. and Mifflin، نويسنده , , C. and Noble، نويسنده , , A.J. and O’Keeffe، نويسنده , , H.M. and Rodriguez-Jimenez، نويسنده ,
Abstract :
The existing hydrous titanium oxide (HTiO) technique for the measurement of 224Ra and 226Ra in the water at the Sudbury Neutrino Observatory (SNO) has been changed to make it faster and less sensitive to trace impurities in the HTiO eluate. Using HTiO-loaded filters followed by cation exchange adsorption and HTiO co-precipitation, Ra isotopes from 200 to 450 tonnes of heavy water can be extracted and concentrated into a single sample of a few millilitres with a total chemical efficiency of 50%. Combined with beta–alpha coincidence counting, this method is capable of measuring 1.5 × 10 - 3 μ Bq / kg of 224Ra and 3.3 × 10 - 3 μ Bq / kg of 226Ra from the 232Th and 238U decay chains, respectively, for a 275 tonne D 2 O assay, which are equivalent to 4 × 10 - 16 g Th/g and 3 × 10 - 16 g U / g in heavy water.
Keywords :
Sudbury Neutrino Observatory , thorium , Liquid scintillation , Ion exchange , radium , Hydrous titanium oxide
