• F.H. O'Shea, G. Marcus, J.B. Rosenzweig
  UCLA, Los Angeles, California
• J. Bahrdt, A. Gaupp
  BESSY GmbH, Berlin
• F.J. Grüner, R. Weingartner
  LMU, Garching

The fundamentals of insertion device physics demand that to have access to ever higher photon energies either the beam energy must increase or the undulator period must decrease. Recent advances in accelerator technology have increased beam energies and at the same time insertion device technology has developed creative ways of producing light of the desired energy, characteristics and quality. This paper describes the simulation work for the design of a 9 mm period in-vacuum planar undulator using a new rare-earth magnetic material.

• J. Bahrdt, J. Feikes, W. Frentrup, A. Gaupp, M.V. Hartrott, M. Scheer, G. Wüstefeld
  HZB, Berlin
• J. Kuhnhenn
  FhG, Euskirchen
• G. Ulm
  PTB, Berlin

The 0.6 GeV storage ring Metrology Light Source (MLS) is in operation since April 2008. Recently, Cherenkov glass fibers have been installed for a temporal and spatial detection of electron beam losses. Based on this information the loss mechanisms can be studied in detail and the performance of the machine can be optimized. First experiments with this diagnostic tool will be presented.

• J. Bahrdt, W. Frentrup, A. Gaupp, M. Scheer
  HZB, Berlin

The UE112 APPLE undulator operated at BESSY II covers the low photon energies down to the visible regime. Below 100eV the state of polarization is significantly modified by the optical components of the beamline. Moving independently three magnet rows of the APPLE undulator (universal mode) any state of polarization can be produced which permits the compensation of the beamline effects. Thus, circularly polarized light can be provided at the experiment. The dynamic multipoles of the universal mode can be compensated with flat wires which are glued onto the vacuum chamber. Simulations and first experiments with the electron beam related to the dynamic multipoles and their compensation are presented.