Experimental characterization of the insertion device effects on beam dynamics at soleil

SOLEIL, the French 2.75 GeV third generation light source, is delivering photons to beam lines in routine operation since January 2007. The storage ring is presently equipped with 14 insertion devices. Commissioning the insertion devices consists in characterizing all the effects on beam dynamics in terms of closed orbit distortion, focusing, chromaticity, coupling, injection efficiency, beam lifetime and sensitivity to working point. We will focus here on the significant effects observed with some undulators. INTRODUCTION The SOLEIL storage ring is now operating with 11 insertion devices (IDs) and 3 new ones have been installed during the last shutdown period in May 2008 (Table 1). During operation, the Users have the full control of their undulators [1]. It is then important to identify expected and unexpected effects for each undulator and all together in different configurations. The first step was to compensate for orbit distortions introduced by residual first order field integrals in order to reach the required μm position stability during field variations. This significant work is still in progress and reported in detail in [2] and [3]. In parallel, a systematic characterisation of each undulator is performed for each configuration of field and phase. We will present here the more significant effects, their analysis in terms of beam dynamics and a comparison with calculation (using field maps generated by RADIA code [4]) and magnetic measurements. Table 1: Insertion device main characteristics. Number Name Type Period (mm) Length (m) 4 U20 In vacuum 20 2.0 1 HU44 Apple II 44 1.6 2 HU52 Apple II 52 1.6 3 HU80 Apple II 80 1.6 3 HU256 Electromagnetic 256 3.1 1 HU640 Electromagnetic 640 10