Asymmetric Immersed Pole Undulators for Advanced Radiation Sources

The development of undulator radiation sources has profoundly impacted a broad range of science and technology, providing unique capabilities for exploring matter at size and time scales from the subatomic to the microwave. Advances in undulator magnet systems are required to extend the range and performance of these sources. Existing undulators have shortcomings as the period is decreased and require complex support systems to achieve high-field and in-vacuum operation. Calabazas Creek Research Inc. (CCR) is proposing to develop the Asymmetric Immersed Pole (AIP) undulator as a high field, short period undulator for light sources. An AIP undulator uses soft magnetic materials arranged so as to convert axial magnetic field into transverse field. A significant feature is low part count per period, making AIP undulators excellent candidates for short period designs. The high transverse magnetic field and the low construction, operation, and maintenance costs of AIP undulators would increase the range and practicality of beam-based radiation systems. Commercial applications and other benefits: In addition to extending the range and performance of high-energy radiation sources, AIP undulators would significantly improve the practicality of lower energy systems, i.e. free- electron lasers (FELs). There are numerous applications at high-GHz, THz, and IR frequencies requiring power levels and/or wavelength tuning beyond existing sources. The cost, size, and radiation shielding requirements of present FEL systems are incompatible with most of these applications. Development of high-field, short period undulators could transform FELs into practical solutions for these applications. We anticipate that the low construction, operation, and maintenance costs of an AIP undulator would significantly increase the practicality of FEL systems at lower beam energies.