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Feikes, J.

 
Paper Title Page
MOPCH053 Towards Sub-picoseconds Electron Bunches: Upgrading Ideas for BESSY II 157
 
  • G. Wuestefeld, J. Feikes, P. Kuske
    BESSY GmbH, Berlin
  
  Sub-picoseconds bunches were achieved with the BESSY low alpha optics, and their lengths were measured using Fourier Transform spectroscopy*. To avoid the coherent synchrotron radiation instability, the current in these short bunches has to be limited to theμampere level. An upgrade of the BESSY II rf gradient to much larger values is suggested to overcome this low current limitation by two orders of magnitude. Intense, picoseconds long bunches could then be achieved already at the regular user optics. The resulting short and very intense electron bunches are useful for generation of short x-ray pulses and powerful THz-radiation. Expected parameters of bunch length and current are discussed.

*J. Feikes et al. "Sub-Picoseconds Electron Bunches in the BESSY Storage Ring", EPAC'04, Luzerne (Switzerland), July 2004.

 
TUOBFI01 A Diagnostic Kicker System as a Versatile Tool for Storage Ring Characterisations 974
 
  • O. Dressler, J. Feikes, J. Kolbe
    BESSY GmbH, Berlin
  
  For the BESSY II Synchrotron Light Source two diagnostic kicker systems including current pulsers were developed, allowing vertical and horizontal deflection of the stored beam. Synchronised with the revolution trigger, simultaneous pulsing of the systems kicks the stored beam in any transverse direction with a repetition rate of up to 10 Hz allowing a wide range of storage ring investigations. Examples are dynamic aperture measurements and frequency map measurements. Special efforts were made to assure the demands of high amplitude and time stability for this kind of experiments. The technical concept of the systems and the controlling of the measurements are described.  
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WEPLS115 Impedances in Slotted-Pipe Kicker Magnets 2649
 
  • F. Marhauser, O. Dressler, V. Duerr, J. Feikes
    BESSY GmbH, Berlin
  
  Storage ring slotted-pipe kicker magnets based on the DELTA design are foreseen for the Metrology Light Source (MLS) of the Physikalisch-Technische Bundesanstalt currently under construction near the BESSY site. Although the slotted pipe maintains the cross-section of the storage ring vacuum chamber, image currents have to bypass the slots generating wakefields. Actually modes with substantial impedances have been revealed by simulations and verified by measurements of a kicker model for the MLS.  
THPLS014 Status of the Metrology Light Source 3299
 
  • K. Buerkmann-Gehrlein, M. Abo-Bakr, W. Anders, P. Budz, O. Dressler, V. Duerr, J. Feikes, H.G. Hoberg, D. Krämer, P. Kuske, R. Lange, J. Rahn, T. Schneegans, D. Schueler, E. Weihreter, G. Wuestefeld
    BESSY GmbH, Berlin
  • R. Klein, G. Ulm
    PTB, Berlin
  
  For more than 25 years, the Physikalisch-Technische-Bundesanstalt (PTB) uses synchrotron radiation at the storage rings BESSY I and II for photon metrology in the spectral range of UV to x-rays. Since decommissioning of BESSY I (1999), there is a gap in the spectral range of UV and EUV wavelength due to the higher electron energy of BESSY II. Thus, in 2003, the Metrology Light Source (MLS), a low energy electron storage ring, was approved, as central instrument in the future Willy Wien Laboratory (WWL). Design, construction and operation of the MLS are realized by BESSY, based on the PTB requirements for a permanent accessible radiometry source, optimized for the spectral range between UV up to VUV. The MLS is tuneable in energy between 200 MeV and 600 MeV, designed for currents between 1pA up to 200mA. Civil construction of WWL in the close vicinity to BESSY is nearing completion. The first MLS components will be installed in spring 2006, commissioning of the 100MeV Microtron is scheduled for summer 2006, while commissioning of the storage ring will start in spring 2007. Regular user operation will begin in January 2008. A status and an overview on the construction of the MLS are  
THPLS017 Orbit Stability in the 'Low Alpha' Optics of the BESSY Light Source 3308
 
  • R. Müller, J. Feikes, P. Kuske, G. Wuestefeld
    BESSY GmbH, Berlin
  
  Running the light source during dedicated shifts in the so-called 'low alpha' mode, BESSY serves two major user groups: THz experiments take advantage of intense, coherent synchrotron radiation (CSR) generated by the short bunches. Time resolved experiments appreciate the very short, high intensity VUV and x-ray pulses in the ps range that help, e.g., prepare the high resolution, low intensity fs-slicing experiments. In the 'low alpha' mode, the sensitivity of the storage ring with respect to energy and horizontal orbit is increased by orders of magnitude while the user experiments require the same beam stability as in 'normal' mode. In this paper an overview of the operational conditions of this specific user mode, the stabilization measures taken, observations and available diagnostic results as well as the achievements and shortcomings of the adapted slow orbit feedback are given.