The goals of high spatial resolution and high elemental sensitivity in the imaging microanalysis of biological tissues and materials have, to a large extent, been attained by using the method of secondary ion mass spectrometry (SIMS) following bombardment of a sample surface by a focused beam of heavy ions. The instrument that we will discuss and which has achieved these goals is a scanning ion microprobe originally developed in collaboration with Hughes Research Laboratories (UC-HRL SIM). It utilizes a 40-60 keV Ga+ probe, extracted from a point-like liquid metal ion source, that can be focused to a spot as small as 20 nm in diameter. During the past five years, much effort has been devoted to a reappraisal of well known SIMS methodologies in regard to their applicability to a range of lateral resolution (20-1000 nm) previously unexplored. Furthermore, of particular concern has been the identification of research areas whose demands could most profitably be matched by the performance of this new class of microprobes. The results of this effort are contained in over 21 topical publications and 14 review articles covering both instrumental aspects of our development and applications to a variety of interdisciplinary problems.
Correlative Electron Microscopy, High Resolution Ion Imaging and Secondary Ion Mass Spectrometry for High Resolution Nanoanalytics on Biological Tissue