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A cryogen-free cryostat for a superconducting undulator with a period of 15 mm (SU15) was developed at the National Synchrotron Radiation Research Center (NSRRC). A 0.44 mm-thin superconducting NbTi wire was wound on iron pole with a racetrack profile. The design field strength of SU15 was 1.4 T and the coil had 148 turns/pole at 230 A; the magnet gap was 5.6 mm. The liquid helium (LHe) recondensation cryostat was designed for SU15. The cryostat provides the advantage of uniform cooling and reduces the amount of LHe consumed. A 0.3 mm-thick stainless steel (SS) beam duct was formed to separate the vacuum in the storage ring from the magnet. Therefore, all of dirty material is produced out of storage ring vacuum. Most of the heat leaked from the LHe vessel leaks from the LHe-fill port heat leak and the 300 K-4.2 K beam duct or was associated with image current power dissipation (ICPD) and bending magnet power dispersion (BMPD). The leaking of heat from the main coil was prevented by the high-temperature superconducting current leads (HTSC). The beam duct was coated with a copper layer with a high-RRR ratio to reduce image current heating. The heat loads on the magnet were cooled using two 1.5 W Gifford-MacMahon (GM) type cryocoolers via LHe medium. [ABSTRACT FROM AUTHOR]

A superconducting wiggler with a magnetic period of 6.0 cm (SW6) and a peak field of 3.2 T has been designed and fabricated in the National Synchrotron Radiation Research Center (NSRRC). The beam duct separates the electron beam from the cryogenic system of the magnet. The heat load on the beam duct should be low to stabilize the operation of the superconducting magnets. However, outgassing caused by synchrotron radiation at an electron energy of 1.5 GeV and a current of 200 mA must be reduced. Accordingly, operating the system at a higher temperature can minimize the adsorption of molecules on the beam duct. Therefore, the beam duct system and its connection by finite element analysis are designed to optimize the operating temperature of the beam duct at between 100 and 120 K. Performance of the beam duct is established to comply with specifications during the operation of magnet. [ABSTRACT FROM AUTHOR]

Mini-pole (short period) in-vacuo superconducting undulators, a vert5ical-winding racetrack coil structure, a horizontal-winding racetrack coil structure and a staggered array structure, were studied for use in the X-ray source in a 1.5 GeV or a medium-energy 3 GeV storage ring. The magnetic arrays are all installed in the ultra-high vacuum environment, required for passing electron beams. In a periodic length of 15 mm and a gap of 5 mm, field strengths of 1.5 T, 1.5 T and 0.7 T can be generated in the three different structures, respectively. Additionally, the staggered undulator with variable-period length or a translator structure with different periodic length can yield various deflection parameters k, by driving a longitudinal solenoid field of 0.8 T. Accordingly, this study addresses the magnet structure of and mechanism of the magnet, and the advantages and disadvantages of the structures of these undulators. The spectral characteristics and the magnetic field features of these undulators are also studied. [ABSTRACT FROM AUTHOR]