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Eichhorn, R.

Paper Title Page
MOPCH186 First Cool Down of the Juelich Accelerator Module Based on Superconducting Half-Wave Resonators 496
 
  • F.M. Esser, B. Laatsch, H.S. Singer, R. Stassen
    FZJ, Jülich
  • R. Eichhorn
    TU Darmstadt, Darmstadt
 
  In the context of upgrading the existing proton and deuteron accelerator facility COSY at the Forschungszentrum Juelich, an accelerator module based on superconducting half wave resonators is prototyped. Due to beam dynamics, the requirements of cavity operation and a top-loading design for mounting, the cryostat had to be designed very compact and with a separate vacuum system for beam and insulation vacuum. These restricted requirements lead to very short cold-warm transitions in beam port region and to an unconventional design regarding to the shape of the cryostat vessel. This paper will review the design constraints, gives an overview of the ancillary parts of the module (cavities, tuner, etc.) and will present the results of the first cool-down experiments. Furthermore the future work will be presented.  
WEPCH115 Numerical Simulation and Optimization of a 3-GHz Chopper/Prebuncher System for the S-DALINAC 2185
 
  • N. Somjit, W.F.O. Müller, T. Weiland
    TEMF, Darmstadt
  • R. Eichhorn, J. Enders, H.-D. Gräf, C. Heßler, Y. Poltoratska, A. Richter
    TU Darmstadt, Darmstadt
 
  A new source of polarized electrons with an energy of 100 keV is presently being developed at the superconducting Darmstadt electron linear accelerator S-DALINAC for future nuclear- and radiation-physics experiments. The pulsed electron beam emitted by the photocathode will be cut to 50 ps by a chopper operated at 3 GHz, and further bunch compression down to 5 ps will be achieved by a two-stage prebuncher section. The chopper-prebuncher system is based on similar devices used at the Mainz Mikrotron (MAMI) where the accelerator frequency is slightly smaller (2.4 GHz). For the chopper, a cylindrical resonator operating at TM110 mode is selected to deflect the electron beam onto an ellipse, i.e., both horizontally and vertically. This is simply achieved by particular slits on both ends of the resonator. The prebunching system consists of two cavities. For increasing the longitudinal capture efficiency, the first cavity will be operated at the fundamental accelerator frequency of the S-DALINAC of 3 GHz, and the second cavity at 6 GHz. The cavities are designed to work at the TM010 mode and TM020 mode for the fundamental and first harmonic, respectively.