Insertions devices

Phase I Insertion Devices studies have highly progressed. They concern 6 undulators corresponding to 4 different types. The main characteristics of which are shown in the table below.

In order to complete the range of CASSIOPEE and TEMPO beamlines towards the highest scope of energy, a second module, respectively HU60 and HU40, will be added in phase II. Furthermore, two other HU256 have already been ordered for the beamlines ANTARES and PLEIADES and two other HU80 for the beamlines PLEIADES and MICROFOC, for the beginning of Phase II.

This undulator is able to provide light with all kinds of polarization, from circular to linear with variable phasing. The original electromagnetic structure consists of three set of coils. One set is used to generate the horizontal component Bx, the two other sets, shifted by a ¼ period from one another, are used to generate the vertical component Bz. The relative adjustment of the currents in the coils generating the vertical component Bz is used to adjust continuously the phasing between Bx and Bz. The Bx field can be reversed (-Bxmax to + Bxmax) in 0.2s at 1 Hz frequency.

In order to avoid field non-linearity with the currents of the different types of coils, and to ensure a good temporal response, we have chosen a design without iron poles or mechanical motion.

The magnet assembly consists of an alternated succession of 12 vertical dipoles and 12 horizontal dipoles respectively generating the Bx and Bz components, each component being shifted from one another by a ¼ period.

The H shape of these dipoles (contrary to the usual “8” shape) leads the magnetic field to propagate in the transverse plane and consequently reduces the cross-talk between the components. This configuration associated with small effective gaps leads to reasonable power supply active power (63 kW). However, such a design is only possible thanks to the NEG (Non Evaporating Getter) coated vacuum chamber, chosen by SOLEIL, that do not need pumping in the median plane.