High-Performance Carbon Materials for Ultracapacitors

65803 Two large hybrid rare earth permanent magnet dipoles have been designed, built, and are now operating in a 70 MeV racetrack microtron. During their development, it was found that the existing rare earth permanent magnet design techniques could be extended to quasi-sheet multipoles to produce pure fields of a desired multipolarity in more compact magnets that are more easily assembled and thus are less expensive. Accordingly, two small quasi-sheet multipole quadrupoles, so-called a-magnets, are now operating in racetrack microtron injection beam lines. This project will use a detailed rare earth permanent magnet quasi-sheet multipole model to design a large dipole for a 35 MeV racetrack microtron. The model can calculate material configurations and geometrical tolerances that will produce gap fields with desired multipolarity, distribution, and uniformity. Phase I will develop the general quasi-sheet multipole model and use it to study gap field distortions, gap field variations with rare earth permanent magnet block placement, and entrance/exit window fringe fields. Local block re-magnetization, as well as steel plate and shimming techniques, will be experimentally investigated. Based on the result, bending dipole magnets for a 35 MeV racetrack microtron will be designed. Commercial Applications And Other Benefits as described by awardee: Compared with electromagnetic dipoles, the superior performance, smaller foot print, comparable capital costs, and smaller operating costs of large high-field quasi-sheet multipole dipoles should provide decisive advantages in fixed field industrial and research accelerators, beam transport lines, spectrometers, and medical imaging applications. Eliminating magnet coils and their power supplies reduces electrical power consumption, servicing costs, control system complexity, and space required while increasing overall reliability.