Particle Tracking in Matter-Dominated Beam Lines

Most computer programs that calculate the trajectories of particles in an accelerator assume that the particles travel in an evacuated chamber. This assumption does not work for muon beams (needed for muon colliders and neutrino factories), which usually are required to pass through matter. Consequently, the trajectory calculation is limited by the lack of user-friendly numerical simulation codes that accurately calculate scattering and energy loss in matter. Geant4, an internationally-supported tracking toolkit that simulates particle interactions in large detectors for high energy physics experiments, includes most of what is known about the interactions of particles and matter. Geant4 has been partially adapted in a program called G4beamline (G4BL) to develop muon beam line designs. This project will continue the development of G4BL to enhance its graphical user-interface and add other features so that it can be used by a larger set of beam line and accelerator developers. In Phase I, the graphical user interface of G4BL will be enhanced for greater effectiveness in beam line design. The program will be debugged and used by accelerator physicists studying muon cooling channel designs and other applications. A plan to include space-charge effects in G4BL will be developed. Commercial Applications and Other Benefits as described by the Applicant: New discoveries and inventions in muon beam cooling in the last four years have increased the probablility that muon colliders and neutrino factories will be the discovery machines of the future. A sophisticated tracking code should find use in the design and development of these machines, enhancing the likelihood that one or more of them will be built.