• C.W.O. Ostenfeld, M. Pedersen
  Danfysik A/S, Jyllinge

Danfysik A/S has built a cryogenic in-vacuum undulator for Diamond Light Source, with a period length of 17.7 mm and an effective K of 1.7 at cryogenic temperatures. The undulator is hybrid-type, with Vanadium Permendur poles and NdFeB poles. In order to verify the performance of the device under cryogenic conditions, an in-vacuum measuring system is required. We present the magnetic measurements at room temperature and under cryogenic in-vacuum conditions. The magnet assembly cannot be baked, due to a choice of high-remanence, low coercivity magnet grade. We discuss the vacuum performance of the undulator.