Imaging SIMS with an accelerator (and biomedical applications)

The combination of a scanning secondary ion source and an accelerator mass spectrometer is a powerful tool for performing imaging secondary ion mass spectrometry, offering various fundamental and operational advantages over conventional high performance magnetic sector instruments. Not only are lower concentrations detectable by AMS, but even at conventionally measurable levels the analysis of desirable surface areas (even greater than can be achieved conventionally with dynamic emittance matching) can be simpler, more sensitive and/or faster by AMS. This is principally a consequence of the large and constant spectrometer acceptance. These benefits are being explored with developments of the Oxford 14C-AMS system. This method is ideally suited to quantitative imaging of radiocarbon labels widely employed in biomedical research to tag specific molecules, is capable of the most sensitive detection and submicron resolution and potentially offers considerable advantages over traditional radiographic imaging. (orig.)