Objective Polepiece in EMs
- Practical Electron Microscopy and Database -
- An Online Book -



This book (Practical Electron Microscopy and Database) is a reference for TEM and SEM students, operators, engineers, technicians, managers, and researchers.



Glaser’s famous bell-shaped model suggested that in order to attain the minimum focal length and the minimum aberrations of a magnetic lens used in a TEM the specimen should be put at the middle of the gap of a pair of symmetrical polepieces [1], e.g. called objective polepiece.

A strong upper-objective polepiece is needed to create a convergent beam to form a CBED (convergent-beam electron diffraction) pattern.

Figure 4258 shows the schematic illustration of EBSD setup in a SEM system. The objective pole piece of the system is indicated. The working distance for EBSD is roughly between 8 and 45 mm.

Objective Polepiece in EMs

Figure 4258. The schematic illustration of EBSD setup in a SEM system.

Note that in some cases, special objective pole pieces need to be designed for particular applications, for instance, in situ STM-TEM applications.






[1] Cosslett, V. E. 1991. Fifty years of instrumental development of the electron microscope, in Advances in Optical and Electron Microscopy, Barer, R. and Cosslett, V. E. Eds., Academic Press, London, 215–267.



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