An isobar separation method with Q3D magnetic spectrometer for AMS

Isobar interference is the main obstacle for AMS measurement, especially in the case of very strong isobaric interference, such as in the measurement of Si-32, Mn-53, Fe-60, Ni-63, etc. An isobar separation method with Q3D magnetic spectrometer was developed aiming at AMS measurements for the above-mentioned nuclides. Based on a method of (Delta E-Q3D) the isobaric events can be largely rejected from the region of the nuclide of interest on the focal plane of a Q3D magnetic spectrometer. As a result, the isobaric interference can be reduced by more than three orders of magnitude. Further reduction of isobaric interference can be achieved by the use of a multi-anode ionization chamber placed at the position of collecting the nuclide of interest. The performance of the Delta E-Q3D system for isobar separation was tested by the above-mentioned nuclides with atomic numbers from 14 to 42. The results showed that Delta E-Q3D method has strong capability for separating isobars, as detailed in this paper. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.