Nuclide analysis of an irradiated tantalum target of a spallation neutron source using high performance ion chromatography and inductively coupled plasma mass spectrometry

Tantalum was used as target material in a spallation source where the neutr ons are produced via spallation reactions between a highly energetic proton beam (E-p approximate to 800 MeV) and the heavy tantalum target. The lanth anide metals were theoretically predicted in the irradiated tantalum target as a major fraction of spallation nuclides with quite significantly differ ent nuclide abundances in comparison to the natural isotopic composition. D ue to expected isobaric interferences of long-lived radionuclides and stabl e isotopes, all the lanthanide metals had to be separated chemically prior to their mass spectrometric determination by high performance ion chromatog raphy (IC) after dissolution of tantalum in a HNO3/HF mixture and separatio n of the tantalum matrix by liquid-liquid extraction. An analytical procedu re was applied for the determination of spallation nuclides of lanthanide m etals in an irradiated tantalum target using IC coupled on-line to a sensit ive double-focusing sector field inductively coupled plasma mass spectromet er (DF-ICP-MS). The experimental results of nuclide abundances of the lanthanides in the ir radiated tantalum target obtained by on-line LC-ICP-MS are in good agreemen t with theoretically calculated values. (C) 1999 Elsevier Science B.V. All rights reserved.