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 neutrons are produced via spallation reactions between a highly energetic proton beam (E(p) approximate to 800 MeV) and the heavy tantalum target. The lanthanide metals were theoretically predicted in the irradiated tantalum target as a major fraction of spallation nuclides with quite significantly different nuclide abundances in comparison to the natural isotopic composition. Due to expected isobaric interferences of long-lived radionuclides and stable isotopes, all the lanthanide metals had to be separated chemically prior to their mass spectrometric determination by high performance ion chromatography (IC) after dissolution of tantalum in a HNO(3)/HF mixture and separation of the tantalum matrix by liquid-liquid extraction. An analytical procedure was applied for the determination of spallation nuclides of lanthanide metals in an irradiated tantalum target using IC coupled on-line to a sensitive double-focusing sector field inductively coupled plasma mass spectrometer (DF-ICP-MS). The experimental results of nuclide abundances of the lanthanides in the irradiated tantalum target obtained by on-line LC-ICP-MS are in good agreement with theoretically calculated values. (C) 1999 Elsevier Science B.V. All rights reserved.