Inverse Design Tool for Ion Optical Devices using the Adjoint Variable Method.

Area of Science:

• Physics
• Computational Science
• Engineering

Background:

• Numerical methods are crucial for ion optical devices (e.g., electron microscopes, mass spectrometers).
• Solving charged particle optics equations analytically is often impossible, making detailed computational analysis and optimization challenging.
• Current methods for analyzing and optimizing ion optical devices are computationally intensive and time-consuming.

Purpose of the Study:

• To present a novel computer-aided design (CAD) tool for ion optical devices.
• To introduce an efficient method for sensitivity analysis and optimization of charged particle optics.
• To overcome the computational burden associated with designing complex ion optical systems.

Main Methods:

• Utilizing the adjoint variable method combined with the finite-element method (FEM) and Störmer-Verlet method.
• Implementing a full sensitivity analysis to quantify the impact of design parameters on device performance.
• Applying gradient-based optimization in conjunction with the adjoint method for shape and voltage optimization.

Main Results:

• Demonstrated a computationally efficient sensitivity analysis for ion optical devices, with cost largely independent of parameter count.
• Successfully performed sensitivity analysis on freeform N-element Einzel lens systems with over 13,000 parameters.
• Achieved optimization of the spot size for these lens systems, showcasing the method's practical application.

Conclusions:

• The adjoint variable method offers a significant computational advantage for the design and optimization of ion optical devices.
• This approach facilitates the optimization of numerous design parameters, including shapes and applied voltages, for complex electrostatic devices.
• The developed CAD tool enables more efficient and effective design of instruments like electron microscopes and mass spectrometers.