U.S. Particle Accelerator School

Numerical Methods for Electron and Ion Source Design course

Sponsoring University:

Rice University


Numerical Methods for Electron and Ion Source Design


John Petillo, SAIC and Stanley Humphries, University of New Mexico

The course covers the latest numerical modeling techniques for analyzing high-current sources and collectors. The new MICHELLE Gun/Collector design code has provided many of these advances. Starting from basic methods for particle tracking in electric and magnetic fields, the course proceeds to the latest finite-element techniques for particle-in-cell simulations. Field modeling topics include structured and unstructured 2D and 3D grids, magnetic fields of relativistic beams, first and second order finite-element expansions, and linear and quadratic cell shapes. Emission models are critical in gun simulations. The course covers techniques for space-charge-limited and temperature-limited emission. Secondary-emission processes dominate the behavior of collectors for energy recovery. We summarize the physics and application issues of recent models for true-secondary and backscattered electrons. The MICHELLE code is used to illustrate incorporation of diverse physical processes into a code architecture. The course includes a hands-on computational laboratory using a 2D finite-element code for Windows 95/98/00/NT. Projects include high-voltage insulator design, converging relativistic guns, beam matching to a PPM array, and multi-stage collector simulations. Students completing assignments will receive an individual software license. Prerequisites: Classical Mechanics and Electromagnetism.