Aligning a featureless thin film in a tem

A method of aligning a thin film in a Transmission Electron Microscope, the Transmission Electron Microscope comprising:

• an electron source for producing a beam of electrons,
• a condenser system for forming a parallel or almost parallel beam of electrons on a sample plane,
• an objective lens for focusing the parallel or almost parallel beam on the diffraction plane,
• a thin film positioned in or close to the diffraction plane or a plane conjugated thereto, the thin film being a featureless thin film,
• an imaging system for forming an enlarged image of the sample plane or the diffraction plane onto an image plane,
• a detector for recording images formed on the image plane,
• the method comprises comprising the steps of:
• focusing the condenser system with a first excitation associated with a first position of the diffraction plane,
• illuminating the thin film with the focused beam of electrons, repeatedly;
• recording an image,
• deriving from the recorded image whether the illumination is an on-plane illumination or an off-plane illumination, the on-plane illumination occurring when the thin film is located in the diffraction plane or a plane conjugated thereto and the off-plane illumination occurring when the thin film is located in a plane that does not coincide with the diffraction plane or a plane conjugated thereto, and
• changing the excitation of at least one lens to change the position of the diffraction plane or a plane conjugate thereto or changing the position of the thin film along the optical axis, until the illumination is an on-plane illumination.