We have developed an x-ray computer tomography (CT) add-on to perform X-ray micro- and nanotomography in any
scanning electron microscope (SEM). The electron beam inside the SEM is focused on a metal target to generate x-rays.
Part of the X-rays pass through the object that is installed on a rotation stage. Shadow X-ray images are collected by a
CCD camera with direct photon detection mounted on the external wall of the SEM specimen chamber. An extensive
description on the working principles of this micro/nano-CT add-on together with some examples of CT-scans will be
given in this paper. The resolution that can be obtained with this set-up and the influence of the shape of the electron
beam are discussed. Furthermore, possible improvements on this SEM-CT set-up will be discussed: replacing the backilluminated
CCD with a fully depleted CCD with improved quantum efficiency (QE) for higher energies, reduces the
exposure time by 6 when using metal targets with x-ray characteristic lines around 10 keV.