The main generators of radiation in fourth-generation sources are insertion devices which are installed in special straight sections of light sources. Multipole magnetic systems such as wigglers and undulators are used to produce high brightness due to a large number of magnetic poles. Multipole magnetic systems are manufactured using conventional electromagnets, permanent magnets, and superconducting magnets. A multipole wiggler/undulator type magnet is a sequence of magnets with a changing sign of the transverse field along the electron orbit. The main characteristics of such magnetic systems are the field amplitude, the period of field change, and the pole gap into which a chamber with an ultra-high vacuum is inserted for the electron beam. Despite the progress in the development of permanent magnet systems, the use of superconducting magnets has a fairly large advantage in creating multipole magnetic systems with identical geometric dimensions. The most common material used for superconducting magnets is niobium-titanium alloy in a NbTi/Cu copper matrix.
The report provides an overview of superconducting insertion devices already used in various synchrotron radiation centers and are planning to be used in the future on 4+ generation light sources.