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Paal, A.

Paper Title Page
MOPCH093 Design of the Double Electrostatic Storage Ring DESIREE 252
 
  • P. Löfgren, G. Andler, L. Bagge, M. Blom, H. Danared, A. Källberg, S. Leontein, L. Liljeby, A. Paal, K.-G. Rensfelt, A. Simonsson
    MSL, Stockholm
  • H. Cederquist, M. Larsson, S. Rosén, H.T. Schmidt, K. Schmidt
    FYSIKUM, AlbaNova, Stockholm University, Stockholm
 
  A double electrostatic storage ring named DESIREE is under construction at the Manne Siegbahn Laboratory and Stockholm University. The two rings will have the same circumference, 9.2 m, and a common straight section where merged beam experiments with ions of opposite signs will be performed. The whole structure will be contained in a single vacuum vessel resulting in a very compact design. In addition to its unique double ring structure it will be possible to cool DESIREE down to 10-20K using cryogenerators. This will reduce the internal vibrational and rotational excitations of stored molecules. A cold system will also result in excellent vacuum conditions where longer lifetimes of the stored beams can be expected. While the ion optical calculations have entered a final phase much of the work is now devoted to solve many of the mechanical and cryogenic challenges of DESIREE. In order to test the mechanical and cryogenic properties of for example insulators, vacuum seals, and laser viewports a small test system has been built. The test system is expected to provide valuable information for the final design of DESIREE.  
TUPCH080 Bunched Beam Current Measurements with 100 pA rms Resolution at CRYRING 1196
 
  • A. Paal, A. Simonsson
    MSL, Stockholm
  • J. Dietrich, I. Mohos
    FZJ, Jülich
 
  In CRYRING molecular beams with currents down to 1 nA are used for experiments. To extend the rms resolution of the bunched beam current measurements down to 100 pA, a BERGOZ Integrating Current Transformer (ICT) and one of the the capacitive pick-up's sum signal are integrated simultaneously. The absolute calibration of the pick-up integrator signal is carried out at the end of the acceleration stage, during 20-60 ms. The ion beam current can be measured over a pulse width range of 100 ns to 15 us with a 20-60% bunch duty cycle. For both detectors, low noise amplifiers and a differential input double integrator have been designed. A programmable phase shifter allows measurement of the beam current during the acceleration of the ions, generating a gate signal with proper phase for the integrators in the 30 kHz-3 MHz frequency range. The bandwidth of the integrators used is 100 Hz.