Does a monochromator improve the precision in quantitative HRTEM?

• Published in: Ultramicroscopy Vol. 89; no. 4; pp. 275 - 290
• Main Authors: den Dekker, A.J., Van Aert, S., Van Dyck, D., van den Bos, A., Geuens, P.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.2001; Elsevier Science
• Subjects: Data processing; Electron microscope design and characterization; Electron sources; Electron, positron and ion microscopes, electron diffractometers and related techniques; Exact sciences and technology; High resolution transmission electron microscopy (HRTEM); Image processing; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Physics; 42.30.W; 61.16.B; 035; Subject index terms: 001; Image processing; 07.05.Fb; 43.50.+y; Data processing; Electron microscope design and characterization; Electron sources; 041; High resolution transmission electron microscopy (HRTEM)
• DOI: 10.1016/S0304-3991(01)00089-4
• ISSN: 0304-3991

This paper addresses the question as to what extent the incorporation of a monochromator in an electron microscope can enhance the performance of high resolution transmission electron microscopy (HRTEM). The monochromator will reduce the chromatic aberration, and hence the information limit, at the expense of beam current, leading to a decrease in signal intensity and a corresponding decrease in signal-to-noise ratio (SNR). Both aspects, information limit and SNR, have been included in a quantitative evaluation based on the statistical precision with which the position of an atom column can be estimated. It is shown that the effect of a monochromator on the attainable precision depends on the microscope and monochromator parameters, as well as on the characteristics of the object.