Design and construction performance of a compact cryogen-free superconducting wavelength shifter

A compact cryogen-free superconducting wavelength shifter with a warm bore for electron beam has been constructed for generating synchrotron radiation hard X-rays. This magnet consists of three pairs of racetrack NbTi superconducting coils that can produce a maximum magnetic field of 6.0 Tesla at the central pole. The superconducting coils, the aluminum supporting block, and the return iron yokes are cooled to 4 K, and the thermal shielding and HTS current leads to 60 K, by using a 1.5 W Gifford-McMahon type cryocooler. The technical issues on the magnet design and the construction process are presented. Several different measurement systems are used to characterize the magnetic field performance.