LAUSR

Many materials have regions of interest (ROIs) that are beneath the surface. A focused ion beam (FIB) is used to remove material at the microscale in order to expose these subsurface ROIs for analysis [1]. When the ROI is to be analyzed using high-resolution analytical electron microscopy, the sample must be very thin (>100 nm) in order to allow transmission of electrons through the sample. The FIB is used not only for ROI extraction but also for thinning the sample to electron transparency [2]. However, when the ROI is more than a few microns beneath the surface and is surrounded by a mineralogically heterogeneous matrix, as is the case for most meteorites, it can be challenging to uniformly thin the ROI to >100 nm.