Tunable Permanent Magnet Quadrupole Operating at Cryogenic Temperatures for Accelerators

In recent years, short period undulators become widely used in synchrotron radiation facilities. When installed in a storage ring, thermal stabilization and vacuum bakeout at high temperatures around 420K are necessary for the magnets. High coercivity magnets are also favored to minimize thermal demagnetization during these processes. Permanent magnets (PMs) that operate cryogenic temperatures offer the possibility of increased performance of the cryogenic PM undulators. Developing magnetic optics, in particular PM quadrupoles, would provide significant advantages in beamline design for future accelerators. The development of this technology would be widely applicable to many fields investigating material properties at low temperatures in strong magnetic fields provided for a large potential market. This project will develop a design for a compact and tunable quadrupole using EEC’s rare earth magnet materials for cryogenic undulator applications. This new design incorporates proven features from the prior work, advanced PM material, and assembly ‘know-how’. Based on previous experience in design and development of both iron dominant quadrupoles and Halbach quadrupoles, EEC will come up with an innovative field adjustment idea using tuning magnets. These novel ideas will enable us to develop a compact and cost-effective quadrupole magnet that will achieve the field requirements and be superior to the current designs. Given the above mentioned advantages of EEC magnet materials and production experience, this project proposes the design and development of a tunable PM-based quadrupole for the future cryogenic undulators. In Phase I, starting with the technical specifications of the general design and magnet parameters, we will proceed with quadrupole magnet design and optimization including fine field tuning features, sample magnet production and magnetic testing. Phase II efforts will aim in building two prototypes of PM quadrupole assemblies for real beamline tests at SLAC National Accelerator Laboratory. Phase III will focus on commercialization and technology dissemination for the quadrupole magnet. The proposed PM technology has the potential to bring a paradigm shift in accelerator technology, replacing conventional electromagnets for many existing applications and allowing the development of new applications. This technology will also bring significant cost savings to the construction, operation, and maintenance of accelerators.