C60+ Secondary Ion Microscopy Using a Delay Line Detector

摘要

Buckminsterfullerene (C60) as a primary ion for secondarynion mass spectrometry (SIMS) has shown manynbenefits over classical SIMS sources in the analysis ofnlarge organic molecules including many of biologicalnsignificance. One constraint has been the limitednfocusing capabilities of the C60n+ beam. Although thisncould be circumvented by using beam size limitingnapertures at the cost of beam current, high-resolutionnimaging using conventional time-of-flight (TOF) instrumentsnhas been challenging and time-consuming. Wenpresent a method in which we combine the use of annunfocused C60n+ beam with an ion optical microscope.nA delay line detector is used to obtain fully resolvednhyperspectral data sets that contain both the full massnspectral and the localization information. The obtainednimage resolving power is 4 μm at a pixel size of 250nnm. Microscope mode C60n+ imaging was shown tonresolve micrometer-scale features in a combinednpolymer-tissue sample. Our new approach demonstratesnhigh-quality SIMS imaging using the full C60n+nbeam current. This results in equal or better resolvingnpower at reduced acquisition speed.