A scanning transmission electron microscope is adapted to acquire high quality precession electron diffraction (PED) patterns by means of separated scanning deflectors and precession deflectors. Magnetic or electrostatic deflectors may be used for scanning and for precession. This enables independent optimization of parameters for each deflection system to achieve a broad operating range simultaneously for both deflection systems.

A transmission electron microscope capable of obtaining a hollow-cone dark-field image and visually displaying irradiation conditions thereof includes an irradiation unit for irradiating a specimen with an electron beam, an objective lens for causing the electron beam transmitted through the specimen to form an image, beam deflectors positioned higher than a position where the specimen is placed, an objective movable aperture for passing only a portion of the electron beam transmitted through the specimen, and a deflection coil control unit. The deflection coil control unit controls a deflection angle of the electron beam using the beam deflectors such that the specimen is irradiated with the electron beam at a predetermined angle with respect to an optical axis while the electron beam is moving in a precessional manner and only a diffracted wave and/or a scattered wave having a desired angle passes through the objective movable aperture.

The present disclosure provides a method of reducing coma and chromatic aberration in a charged particle beam device for providing a beam tilt of a charged particle beam. The method includes tilting the charged particle beam with a deflection assembly consisting of two or more electrostatic deflection elements, wherein at least one deflection element of the two or more deflection elements is a post-lens deflector, while the charged particle beam is guided through an essentially coma-free z-position of an objective lens, and reducing off-axis chromatic aberrations with a magnetic deflection element, wherein tilting the charged particle beam reduces coma independent of off-axis chromatic aberrations.