Skip to main content

Study of quadrupole-octopole Cc corrector for the large gap HREM

Buy Article:

$28.45 plus tax (Refund Policy)


We have considered several aspects of a quadruplet of quadrupole-octopoles aimed at the Cc -correction of a high resolution TEM with large-gap pole piece and low beam energy. The strategy of adding appropriate numbers of octopoles to balance the third order aperture aberrations and correct coma is discussed in detail. We also numerically studied the behavior of several resolution-limiting factors as functions of the focal length and chromatic aberration of the objective lens. For the purpose of comparison, the calculation used on two models: the Gaussian thin lens model and rectangular thick lens model, as extreme cases of the real quadrupole-octopole field distribution. We conclude that for a moderate electrode potential of the electrostatic quadrupole, its power stability poses the the most severe limit on the achievable resolution. It is expected that as long as the power instability of its electrostatic quadrupoles can be maintained below 0.1 ppm, a quadrupole-octopole quadruplet Cc corrector featuring thick field distribution can provide a correction of Cc up to 6.5 mm without inducing any other aberration effects.

Keywords: High resolution TEM; chromatic aberration; electron optics; octopole; quadrupole

Document Type: Original Article


Affiliations: Department of Physics, 1110 W. Green Street, University of Illinois, Urbana, IL 61801, USA

Publication date: January 1, 2002


Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more