New sample holder geometry for high precision isotope analyses.

Secondary ion mass spectrometry is applied to a wide range of Geoscience applications because of its capability to provide direct in situ measurement of elemental and isotopic composition. The CAMECA IMS 1280 and 1280-HR are large geometry ultra-high sensitivity ion microprobes that provide excellent precision and reproducibility for isotope ratio measurements. A precision at the tenth permil level is routinely achieved for the measurement of 18O/16O ratio from 10 µm spots using multicollection Faraday Cups. However, analytical artifacts related to the surface topography and to the location of the analysis in the sample (X-Y effects) are known to bias the precision for isotope analysis. The X-Y effects have been investigated using a CAMECA prototype sample holder design. Results show a significant improvement in terms of reproducibility for analyses performed over a large area of the sample. Detailed analytical data using the new sample holder will be presented. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]