polepiece

"Polepiece" is a magnetic pole made of a soft magnetic material (pure iron, permendur), which concentrates the magnetic flux produced by the electromagnet and guided by the yoke to produce a strong magnetic field in a narrow gap (space) in the polepiece. Rotationally symmetric strong magnetic fields produced between the upper and lower poles enable electron beams to be focused. Several types of polepieces are available for the objective lens. They include the ultra-high-resolution polepiece that gives a strong magnetic field for high-resolution image observation, the multiuse polepiece that allows a specimen to be tilted at large angles, and the high-contrast polepiece that enhances image contrast.

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