| Paper |
Title |
Page |
| THPC001 |
Synthesis of Optimal Nanoprobe (Linear Approximation)
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2969 |
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- S. N. Andrianov, A. A. Chernyshev, N. S. Edamenko, Yu. V. Tereshonkov
St. Petersburg State University, Applied Mathematics & Control Processes Faculty, St. Petersburg
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High energy focused ion (proton) micro- and nanoprobes are intensively integrated to powerful analytical tool for different scientific and technological aims. Requirements for beam characteristics of similar focusing systems are extremely rigid. The value of demagnification for micro- and nanoprobes is the main optimality criteria, and as desirable value are in the range from 50 to 100 or even more. In the paper, we reconsider the basic properties of first order focusing systems from an optimal viewpoint. The matrix formalism allows us to formulate a nonlinear programming problem for all parameters of guiding elements. For this purpose there are used computer algebra methods and tools as the first step, and then some combination of special numerical methods. As a starting point for nanoprobe we consider so called “russian quadruplet”. On the next steps, we also investigate other types of nanoprobes. Some graphical and tabular data for nanoprobe parameters are cited as an example.
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| THPC002 |
Synthesis of Optimal Nanoprobe (Nonlinear Approximation)
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2972 |
| |
- S. N. Andrianov, N. S. Edamenko, Yu. V. Tereshonkov
St. Petersburg State University, Applied Mathematics & Control Processes Faculty, St. Petersburg
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This paper is a continuation of the paper devoted to synthesis of optimal nanoprobe in linear approximation. Here the main goal is the optimization of nanoprobe including nonlinear aberrations of different nature up to third order. The matrix formalism for Lie algebraic methods is used to account for nonlinear aberrations. This method gives a possibility to consider nonlinear effects separately. Here we mean that a researcher can start or remove different kind of nonlinearities. This problem is separated into several parts. On the first step, we consider possibilities of additional optimization for some structures, selected on the step of linear approximation. The most of aberrations have harmful character, and their effect must be maximally decreased. Therefore, on the next steps, some we use analytical and numerical methods for generation of nonlinear corrected elements. The matrix formalism allows reducing the correction procedure to linear algebraic equations for aberration coefficients. Some examples of corresponding results are given.
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