• H. Delsim-Hashemi, J. Roßbach
  Uni HH, Hamburg
• U. Englisch, T. Mueller, A. Schöps, M. Tischer, P.V. Vagin
  DESY, Hamburg
• I. Vasserman
  ANL, Argonne

A seeded free-electron laser (FEL) experiment at VUV wavelengths, called sFLASH, is being prepared at the existing SASE FEL user facility FLASH. Seed pulses at wavelengths around 35 nm from high harmonic generation (HHG) will interact with the electron beam in sFLASH undulators upstream of the existing SASE undulator section. In this paper the tuning results and performance of the sFLASH undulators are presented.

• E.R. Moog, M. Abliz, K.D. Boerste, T.W. Buffington, D. Capatina, R.J. Dejus, C. Doose, Q.B. Hasse, Y. Ivanyushenkov, M.S. Jaski, M. Kasa, S.H. Kim, R. Kustom, E. Trakhtenberg, I. Vasserman, J.Z. Xu
  ANL, Argonne
• N.A. Mezentsev, V.M. Syrovatin
  BINP SB RAS, Novosibirsk

A number of prototype magnetic structures for a superconducting undulator have been successfully built and tested. The field quality of a test device was measured in a vertical dewar; the phase errors were 7.1 deg. at the maximum design current with no phase shimming. The Advanced Photon Source (APS) specification for overall trajectory was met using the end compensation coils. Several Hall probes have been calibrated at cryogenic temperatures. The design for a cryostat to hold the undulator for installation in the APS storage ring is nearing completion, and a cryogenic measurement facility to measure the magnetic field of the completed undulator is under development.