Abstract: A method for improving the resolution of STEM images of thick samples. In STEM, the diameter of the cross-over depends on the opening half-angle ? of the beam and can be as low as 0.1 nm. For optimum resolution an opening half-angle is chosen at which the diameter of the cross-over R(?) shows a minimum. For thick samples the resolution is, for those parts of the sample removed from the cross-over plane, limited by the convergence of the beam, resulting in a diameter D of the beam at the surface of the sample. The opening angle is chosen to balance the contribution of convergence and of diameter of the cross-over by choosing an opening half-angle smaller than the optimum opening half-angle. Effectively the sample is then scanned with a beam that has a substantially constant diameter over the length of the sample material through which the electrons have to travel.

Abstract: The invention relates to a method for correcting distortions introduced by the projection system (106) of a TEM. As known to the person skilled in the art distortions may limit the resolution of a TEM, especially when making a 3D reconstruction of a feature using tomography. Also when using strain analysis in a TEM the distortions may limit the detection of strain. To this end the invention discloses a detector equipped with multipoles (152), the multipoles warping the image of the TEM in such a way that distortions introduced by the projection system are counteracted. The detector may further include a CCD or a fluorescent screen (151) for detecting the electrons.

Abstract: A method for improving the resolution of STEM images of thick samples. In STEM, the diameter of the cross-over depends on the opening half-angle ? of the beam and can be as low as 0.1 nm. For optimum resolution an opening half-angle is chosen at which the diameter of the cross-over R(?) shows a minimum. For thick samples the resolution is, for those parts of the sample removed from the cross-over plane, limited by the convergence of the beam, resulting in a diameter D of the beam at the surface of the sample. The opening angle is chosen to balance the contribution of convergence and of diameter of the cross-over by choosing an opening half-angle smaller than the optimum opening half-angle. Effectively the sample is then scanned with a beam that has a substantially constant diameter over the length of the sample material through which the electrons have to travel.

Abstract: The invention relates to the extraction of a frozen hydrated sample for TEM (Transmission Electron Microscope) inspection, such as a vitrified biological sample, from a substrate and the attaching of said sample to a manipulator. Such a hydrated sample should be held at a cryogenic temperature to avoid ice formation. By melting or sublimating a part of the sample material outside the area to be studied in the TEM and freezing the material to the manipulator (10), a bond is formed between sample (1) and manipulator. This makes it possible to transport the sample from the substrate to e.g. a TEM grid. In a preferred embodiment a part (2) of the manipulator (10) is held at a cryogenic temperature, and the melting or sublimation is caused by heating the tip (3) of the manipulator by electric heating of the tip and then cooling the tip of the manipulator to a cryogenic temperature, thereby freezing the sample (1) to the manipulator.