Design of Staggered Undulators With Dual Magnet Periods

To generate synchrotron radiation with an extended photon spectral range, a new staggered undulator design capable of switching between two magnet periods is proposed. The magnetic structure of this design consists of one fixed magnet array and three movable ones located in a solenoid coil. For demonstrative purpose, two undulators with a 20/40 mm and 160/320 mm dual magnet periods, respectively, have been designed and their magnetic field and photon brilliance calculated. A superconducting solenoid coil is optimized to produce a highly uniform field over the entire undulator length. The mechanical design of the undulator is also presented.