A new apparatus for electron tomography in the scanning electron microscope

The three-dimensional reconstruction of a microscopic specimen has been obtained by applying thetomographic algorithm to a set of images acquired in a Scanning Electron Microscope. This result was achieved startingfrom a series of projections obtained by stepwise rotating the sample under the beam raster. The Scanning ElectronMicroscope was operated in the scanning-transmission imaging mode, where the intensity of the transmitted electronbeam is a monotonic function of the local mass-density and thickness of the specimen. The detection strategy has beenimplemented and tailored in order to maintain the projection requirement over the large tilt range, as required by thetomographic workflow. A Si-based electron detector and an eucentric-rotation specimen holder have been specificallydeveloped for the purpose.