Status of the ESRF insertion devices

Abstract

The cumulated length of insertion devices in operation at the ESRF reaches 44 m, segmented in 29 devices serving 20 beamlines. The majority are conventional vertical sinusoidal field devices made of permanent magnet. Exotic insertion devices have been installed, such as helical undulators with variable polarization, asymmetric wigglers, a variable gap chamber short undulator and a 5 T superconducting wiggler. With the new low emittance lattice, a single undulator segment generates hard x-rays with a record brilliance of 2x1019 phot./s/.1%/mm2/mr2. All devices have been produced in-house, and the methods of field correction based on shimming are summarized. Recent developments concerning the design of undulator/wiggler terminations are described, which minimize or eliminate the need for electromagnet correctors on hybrid wigglers or allow the implementation of variable length segmented undulators.