Figure 12
From: A new approach for fast field calculation in electrostatic electron lens design and optimization
(a) The results from an optimization of a 4-electrostatic lens system using GA, where the optical parameters are calculated by FOEM (“FOEM + GA”). The graph represents the objective function (OF) values (Y-axis) versus generation (X-axis). The black/blue dots show the best/mean objective function values at each generation. Figure (b) shows the zoomed-in data of figure (a). System B is the best system found in this optimization. ’CT’ stands for the computation time needed to run the optimization until the generation indicated by the green arrow. Figure (c) presents the result of an optimization using GA, called “FOEM + FEM + GA”, with the initial data fed from a previous optimization of “FOEM + GA”. A lens system depicted by C’, is an optimized system resulting from “FOEM + FEM + GA” with OF = 14.32, occurring at generation 2.
