U.S. Particle Accelerator School
Numerical Methods for Electron and Ion Source Design course
Sponsoring University:
Rice University
Course:
Numerical Methods for Electron and Ion Source Design
Instructors:
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.