Tuning High Order Geometric Aberrations in Quadrupole-Octupole Correctors

Tuning fifth-order aberrations in a quadrupole-octupole corrector.

The resolution of conventional electron microscopes is usually limited by spherical aberration. Microscopes equipped with aberration correctors are then primarily limited by higher order, chromatic, and misalignment aberrations. In particular the Nion third-order aberration correctors installed on machines with a low energy spread and possessing sophisticated alignment software were limited by ...

High Order Correctors and Two-scale Expansions in Stochastic Homogenization

In this paper, we study high order correctors in stochastic homogenization. We consider elliptic equations in divergence form on Zd, with the random coefficients constructed from i.i.d. random variables. We prove moment bounds on the high order correctors and their gradients under dimensional constraints. It implies the existence of stationary correctors and stationary gradients in high dimensi...

[Relationship between high-order aberrations and age and between high-order aberrations and refraction errors].

PURPOSE To evaluate the relationship between high-order aberrations and refractive errors, and between high-order aberrations and age. METHODS An analytic retrospective study of patients that underwent aberrometry examination was conducted. All subjects examined with LadarWave aberrometer at the Hospital de Olhos do Paraná from April 2004 to April 2005 were included in this study. The major i...

Quadrupole and octupole radiation from 16O near 39 MeV excitation.

Optimized Quadrupole-Octupole C3/C5 Aberration Corrector for STEM

The ideal location for an aberration corrector in an electron-optical column is at the place where the aberration is introduced. In practice, this of course typically cannot be achieved. The resultant separation between where an aberration is introduced and where it is removed produces combination aberrations for all aberrations of higher than first order. In the case of third-order aberration ...