Development of elliptical undulators for ELETTRA

ELETTRA is presently operating six insertion devices, including an electromagnetic elliptical wiggler. Stimulated by the increasing interest in variable polarization sources, a series of new elliptical undulators has been designed to provide linear, circular and elliptical polarization in a wide spectral range. One of them will feature a quasi-periodic field in order to reduce contamination from high order harmonics. A chicane arrangement is foreseen in one straight section of the ring so that two experimental stations can be operated simultaneously. Two identical undulator segments, together with a phase modulation electromagnet, will be used in an optical klystron configuration for the storage ring FEL project. We present the construction, testing and magnetic measurement results of the first undulator of this kind (EU6.0). Progress with the other devices is also described.