DESIGN OF A NEW-TYPE OF PLANAR UNDULATOR FOR GENERATING VARIABLY POLARIZED RADIATION

A small prototype model of a new undulator is under construction for g enerating variably polarized radiation. This undulator consists of two pairs of planar permanent magnet arrays above and below the electron orbit plane in a storage ring. This device has no magnetic structures in the horizontal orbit plane in order to avoid the conflict with the aperture of the electron orbit. The on-axis magnetic field generated b y shifting the relative position of pairs of magnet arrays in this dev ice induces helical and sinusoidal electron orbit motions. It leads to the generation of circularly and linearly polarized undulator radiati on. This new undulator will be installed in the JAERI storage ring (JS R) in order to examine the performance for generating variable polariz ation.