Heat transfer in beam optics analyzer

Summary form only given. This paper will describe the new capability in BOA, the heat transfer integration with particle simulations. It will discuss implemented techniques to smooth the wall power density field generated by electron energy. It will explain the finite element method with adaptivity used to solve the heat equation, and provide numerical results to demonstrate the implementation. Particle optics analysis tracks particles from their emitting planes to their terminal electrodes. The terminal planes where the electrons exit are the subject of interest in this research. The electrons dissipate their energy on these terminal planes in the form of heat, which can be quantified by a power density field. Due to the ballistic nature of electrons and the linear interpolation from the particle positions and energies to the mesh, the power density field is not smooth nor uniform. One can improve the field fidelity by increasing the number of particles and mesh density on the terminal plane. However, it is probably more practical and efficient to increase the number of particles and apply a higher order of interpolation for the power density field. Results of both approaches to improve field fidelity by increasing surface mesh density and quadratic interpolation will be compared. In existing state-of-the-art analysis tools, the particle simulator is required to output the power density field to an external file. This is in a proprietary format as a boundary condition for another simulation package for heat transfer analysis. This requires the designer to re-import the CAD drawings into the heat transfer package, re-specify the boundary conditions and material properties and re-mesh before performing the analysis to obtain the temperature and stress information. This is time consuming and prone to many errors due to importing geometry and solution fields from one analysis tool to another. It is also expensive to purchase and maintain two different sets of analytic- l tools and the auxiliary codes interfacing the two. Multiphysics capability in BOA will reduce costs and design time. It allows BOA to obtain the power density field from the particle simulation as the heat source for the heat transfer analysis, and on the same geometric model it would solve for the temperature profiles under some prescribed conduction, convective and radiation boundaries. The scalar finite element method with adaptivity solving the heat transfer problems will be presented in detail. Results of particle optics and heat transfer analysis of a simple collector under electron beam heating will demonstrate the implementation.