A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z    

Hofmann, I.

Paper Title Page
TUPLT105 Measurement of Activation Induced by an Argon Beam in a Copper Target at the SIS18 1399
 
  • A. Fertman, A. Golubev, M. Prokuronov, B.Y. Sharkov
    ITEP, Moscow
  • G. Fehrenbacher, R.W. Hasse, I. Hofmann, E. Mustafin, D. Schardt, K. Weyrich
    GSI, Darmstadt
 
  Results of the measurement of activation induced by Argon beam with energies of E=100,200,800 MeV/u in the copper target are presented. The densities of various radioactive isotopes are derived from the measurements. Long-time prediction of radioactivity and accumulated doses in the accelerator equipment is calculated.  
WEPLT029 Intensity Dependent Emittance Transfer Studies at the CERN Proton Synchrotron 1891
 
  • E. Métral, C. Carli, M. Giovannozzi, M. Martini, R.R. Steerenberg
    CERN, Geneva
  • G. Franchetti, I. Hofmann
    GSI, Darmstadt
  • J. Qiang
    LBNL, Berkeley, California
  • R.D. Ryne
    LBNL/CBP, Berkeley, California
 
  An intensive study has been undertaken since the year 2002 to understand better the various high-intensity bottlenecks of the CERN Proton Synchrotron machine. One of these limitations comes from the so-called Montague resonance. High-intensity proton synchrotrons, having larger horizontal than vertical emittance, may suffer from this fourth-order coupling resonance driven by space charge only. In particular, such resonance may lead to emittance sharing and, possibly, beam loss due to vertical acceptance limitation. Experimental observations made in the 2002 and 2003 runs on the Montague resonance are presented in this paper and compared with 3D particle-in-cell simulation results and theoretical predictions.  
WEPLT053 Dynamical Effects of the Montague Resonance 1957
 
  • I. Hofmann, G. Franchetti
    GSI, Darmstadt
  • J. Qiang, R.D. Ryne
    LBNL/CBP, Berkeley, California
 
  In high-intensity accelerators emittance coupling, known as Montague resonance, may be an issue if the tune split is small. For static tunes within the stop-band of this fourth order space charge driven coupling the final emittances may become equal (equipartition). Using 2D computer simulation we show, however, that slow crossing of the resonance leads to merely an exchange of emittances. In 3D this is similar, if the crossing occurs over a time-scale shorter or comparable with a synchrotron period. For much slower crossing we find, instead, that the exchange may be suppressed by synchrotron motion. We explain this effect in terms of the mixing caused by the synchrotron motion.  
WEPLT059 Beam Loss Modeling for the SIS100 1975
 
  • G. Franchetti, I. Hofmann
    GSI, Darmstadt
 
  In long term storage dynamic aperture is typically regarded as the quantity which has to be maintained sufficiently large in order to prevent beam loss. In the SIS100 of the GSI future project, a beam size occupying a large fraction of the beam pipe is foreseen. This circumstance requires a careful description of the lattice magnetic imperfections. The dynamic aperture is estimated in relation with an optimization of the SIS100 working point. For a space-charge-free bunched beam, estimates of beam loss are computed and compared with dynamic aperture. The impact of space charge will be discussed, and preliminary results on its effect on dynamic aperture and beam loss are presented.  
WEPLT060 Linear Coupling Theory of High Intensity Beams 1978
 
  • G. Franchetti, I. Hofmann
    GSI, Darmstadt
  • M. Aslaninejad
    IPM, Tehran
 
  It is planned to use linear coupling in the SIS18 in order to fully or partially equilibrate the transverse emittances before transfer to the projected SIS100 synchrotron. In this paper we show that space charge significantly modifies the coupling mechanism. In particular the width of the stop-band is dominated by the space charge tune shift for weak skew strength. The conditions are discussed, under which slow crossing of the coupling resonance leads to the desired goal of equalizing emittances while maintaining a sufficient matching of the beam to the ring and extraction optics.