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A prototype superconducting undulator with a 1-m magnet array, a magnet period of 15 mm and a magnet gap of 5.6 mm was fabricated to test the performance of the magnetic field and to investigate related issues. The mechanical precision of the entire iron pole construction is within 30 μm. The electric insulation was enhanced with Kapton tape on the entire magnet array between the wire and the iron. A dummy beam duct was assembled with the magnet array and tested in the test dewar. A cryogenic Hall-probe measurement system with a rail guider was assembled with the test dewar to measure the on-axis field distribution. A UHV beam duct was developed and tested in a separate environment to ensure the reliability and to test the aging effect. In this paper, the concept of the magnet design, the related technical issues, the performance of the magnetic field and the magnet training behavior is discussed. [ABSTRACT FROM AUTHOR]

A mini-pole superconducting undulator with a 15mm period length (SU15) was developed at the National Synchrotron Radiation Research Center (NSRRC). The coil was wound by a superconducting (SC) NbTi wire with small dimensions and low Cu/SC ratio. The design field strength of SU15 with 158turns/pole was 1.4T at 215A, and the magnet gap was 5.6 mm. Extra trim coils and poles are mounted on the main iron pole. The trim coils directly compensate for the strength error of the peak field. The prototype racetrack iron pole was fabricated via electric discharge machining to produce a complete set of 40-poles. The coil was impregnated by epoxy and wrapped in Kapton to maintain insulation between coil and iron pole. A substitution beam duct was built and assembled with the magnet array and tested in the test Dewar. The conceptual design of bath liquid helium (LHe) cryostat has to tolerate more image current and radiation heating on the beam duct. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]