Final Technical Report Phase I

Low energy electrons (often referred to as "electron clouds") in the beam chambers of high intensity accelerators and storage rings can limit their performance. They can limit intensity by causing instabilities, unacceptable pressure increases or increases in beam size. Thus, reliable simulations of electron cloud generation in the Los Alamos high intensity Proton Storage Ring (PSR) and similar machines would be a most valuable tool for improving our understanding of its origin, the parameters that affect it and how it might be controlled. Such tools would provide cost-effective methods for designing mitigation measures and evaluating them before going to the expense of fabrication and experimental testing in an operating accelerator facility. In this project we have developed and tested several significant improvements to a widely used electron cloud simulation code, POSINST. In our version, LANLPOSINST V6, we have add several important features including the capability to model a multi-element section of the ring consisting of two quadrupole magnets with 3-dimensional magnetic fields, dipole magnet end fields, several drift spaces and various electron cloud diagnostics. Improvements were also added to the modeling of the initial primary or “seed” electrons from proton beam losses. One important conclusion from benchmarking these improvements was the need to include “seed” electrons produced from secondary particles resulting from the primary proton beam losses