Author: Fraser, M.A.
Paper Title Page
MOPFI059 Design and Performance of the Beam Transfer Lines for the HIE-ISOLDE Project 416
  • A.S. Parfenova, W. Andreazza, J. Bauche, E.D. Cantero, P. Farantatos, M.A. Fraser, B. Goddard, Y. Kadi, A.J. Kolehmainen, D. Lanaia, M. Martino, R. Mompo, E. Siesling, A.G. Sosa, M.A. Timmins, G. Vandoni, D. Voulot, E.S. Zografos
    CERN, Geneva, Switzerland
  Beam design and beam optics studies for the HIE-ISOLDE transfer lines have been carried out in MadX, and benchmarked against Trace3D results. Magnet field errors and alignment imperfections leading to deviations from design parameters have been treated explicitly, and the sensitivity of the machine's lattice to different individual error sources was studied. As a result, the tolerances for the various error-contributions have been specified for the different equipment systems. The design choices for the expected magnet field and power supply quality, alignment tolerances, instrument resolution and physical aperture were validated. The methodology and results of the studies are presented.  
MOPME072 Performance Tests of a Short Faraday Cup Designed for HIE-ISOLDE 646
  • E.D. Cantero, W. Andreazza, E. Bravin, M.A. Fraser, D. Lanaia, A.G. Sosa, D. Voulot
    CERN, Geneva, Switzerland
  Funding: E.D.C, D.L. and A.S. acknowledge CATHI Marie Curie ITN: EU-FP7-PEOPLE-2010-ITN Project number 264330. M.A.F acknowledges co-funding by the European Commission (Grant agreement PCOFUND-GA-2010-267194)
The On-Line Isotope Mass Separator (ISOLDE) facility at CERN is being upgraded in order to deliver higher energy and intensity radioactive beams. The final setup will consist in replacing the energy variable part of the normal conducting REX post-accelerator with superconducting cavities. In order to preserve the beam emittance, the drift space between the cryomodules housing these cavities has been kept to a minimum. As a consequence, the longitudinal space available for beam diagnostics is severely limited in the inter-cryomodule regions. A Faraday cup (FC) will be installed to measure beam currents, and due to the tight spatial constraints, its length is much smaller than usual. This poses a great challenge when trying to avoid the escape of ion-induced secondary electrons, which would falsify the current measurement. Two prototypes of such a short FC have therefore been tested at REX-ISOLDE using several beam intensities and energies, with the aim of determining its accuracy. In this paper the experimental results obtained for the two prototype cups are presented together with numerical calculations of the electrostatic fields that are produced inside the cup.
THPWO076 Design Study for 10 MHz Beam Frequency of Post-accelerated RIBs at HIE-ISOLDE 3933
  • M.A. Fraser, R. Calaga, I.-B. Magdau
    CERN, Geneva, Switzerland
  An increased bunch spacing of approximately 100 ns is requested by several research groups targeting experimental physics at HIE-ISOLDE. A design study testing the feasibility of retrofitting the existing 101.28 MHz REX (Radioactive ion beam EXperiment) RFQ with a sub-harmonic external pre-buncher at the ISOLDE radioactive nuclear beam facility has been carried out as a means of decreasing the beam frequency by a factor of 10. The proposed scheme for the 10 MHz bunch repetition frequency is presented and its performance assessed with beam dynamics simulations. The opportunity to reduce the longitudinal emittance formed in the RFQ is discussed along with the options for chopping the satellite bunches populated in the bunching process.