Challenges in localized high precision isotope analysis by SIMS

In situ isotopic measurements with sputtered ions suffer from mass fractionation related to emission processes modulated by instrumental factors. A selection of possible sources of instrument discriminations are examined and briefly discussed, ion collection optics, unwanted weak magnetic fields, ion counting with electron multipliers and electrical potential stabilization on insulating samples. # 2004 Published by Elsevier B.V.