<title>Interactive design of multicomponent systems</title>

Abstract

Designers of Charged Particle Optics instruments use different levels of complexity to model the components in the system. They may first describe a round magnetostatic lens just in terms of focal distance, later in the design add an estimated spherical and/or chromatic aberration coefficient, perhaps with a value depending on the focal distance. Only in the very last phase, they will use numerical simulation programs to find the magnetic fields and the associated optical properties of a detailed physical design. We are developing a design tool which enables interactive definition of a complete system and its components. An essential feature of this tool is the ability to describe the components at different levels of complexity and then to switch between those levels. For this it is convenient if the program can find some of the parameters necessary for the `new' level of complexity from the `old' level of complexity. For example, it should find typical pole piece dimensions given a focal distance plus spherical aberration coefficient, and vice-versa. The feasibility of these conversions is exemplified by numerical examples from our design tool POCAD.