A DOUBLE FOCUSING MASS-SPECTROMETER FOR GEOCHRONOLOGY

The performance characteristics of a double focusing mass spectrometer designed specifically for geochronology are described. The sensitive high resolution ion micro probe (SHRIMP II) mass spectrometer is ideal ly suited for in-situ analysis of uranium and/or thorium-bearing miner als to provide geochronological information on micron-sized domains of the minerals. SHRIMP II simultaneously meets the requirements of high mass resolution and high ion transmission efficiency together with go od abundance sensitivity. SHRIMP II's excellent spatial and mass resol ution, coupled with its high sensitivity, has enabled zircon geochrono logy to be revolutionized. (Int J Mass Spectrom 178 (1998) 43-50) (C) 1998 Elsevier Science B.V.