APPLE-II Type Quasi-Periodic Variably Polarizing Undulator at HiSOR

Abstract

A newly constructed quasi-periodic APPLE-II undulator was installed in the HiSOR ring at Hiroshima Synchrotron Radiation Center, Hiroshima University during the summer shutdown period in 2011. This 1.8 m-long undulator has a period length of 78 mm. In this article, the mechanism of magnetic field generation for various polarization modes of APPLE undulator, the principle of quasi-periodic undulator, and the performance of HiSOR QP-APPLE-II undulator are described.