stigmator

stigmator

[stig′mäd·ər]
(electronics)
A device that corrects asymmetries in an electron lens by superposing on the field of the lens a second adjustable field.
References in periodicals archive ?
The Vega column consists of a high brightness tungsten electron gun, an electromagnetic beam centering system below the anode, a doublet condenser lens system with a spray aperture, an intermediate lens with its own electromagnetic centering system, and a low-aberration conical objective lens with integrated scanning and stigmator coils.
In addition, astigmatic distortion can be corrected via stigmator coils and the beam can be shifted in X and Y as well as tilted up to five degrees.