A first attempt to measure 92Nb/93Nb ratios with Accelerator Mass Spectrometry

An Accelerator Mass Spectrometry (AMS) method for the measurement of the long-lived radionuclide Nb-92 has been established at the HI-13 Tandem Accelerator of the China Institute of Atomic Energy (CIAE). Niobium powder mixed with PbF2 by a ratio of 1:2 (in mass) was used as the cathode material. Atomic anions of Nb- were extracted from a Cs-beam sputter source. The terminal voltage of the tandem accelerator was 8.5 MV. Nb13+ ions were selected after terminal foil stripping. A multi-anode gas ionization chamber was used for the particle detection. The total suppression factor of the two major interfering isobars, Zr-92 and Mo-92, was about 10(3). A detection limit of about 10(-11) was achieved for Nb-92/Nb-93 ratio measurements on a blank sample. (C) 2012 Elsevier B.V. All rights reserved.