ISO 25387:2026

Microbeam analysis — Analytical electron microscopy — Procedures for determining the point resolution of high-resolution transmission electron microscope

This document specifies a procedure for determining the point resolution, called Scherzer resolution, of high-resolution transmission electron microscopes (HREM), which can visualize sample structure with sub-nanometre fineness. This document also specifies the measurement procedure of the real spherical aberration coefficient of the objective lens used.

The procedure specified in this document for measuring the spherical aberration coefficient uses the dark rings that appear in the fast Fourier transform (FFT) pattern of HREM images of amorphous thin films, in which, at least three dark rings need to be observable near the Scherzer focus. Therefore, this document is applicable to HRTEMs equipped with a cold field emission gun (CFEG), Schottky emission gun (SEG) or thermal field emission gun (TFEG), or HREMs equipped with a thermionic emission gun (TEG) in which three or more dark rings can be clearly observed in the FFT pattern.

This document does not treat the information limits, lattice resolution and STEM resolution. In addition, this document is not applicable to Cs-corrected TEM.