Author: Forck, P.
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TUPG05 Simulation of Bunch Length and Velocity Dependence of Button BPMs for Linacs Using CST Particle Studio® 319
  • M.H. Almalki
    KACST, Riyadh, Kingdom of Saudi Arabia
  • P. Forck, T. Sieber, R. Singh
    GSI, Darmstadt, Germany
  At non-relativistic velocities at a proton LINAC, the electromagnetic field generated by the beam has a significant longitudinal component, and thus the time evolution of the signal coupled to the BPM electrodes depends on bunch length and beam velocity. Extensive simulations with the electromagnetic simulation tool CST Studio® were executed to investigate the dependence of the induced BPM signal on different bunch lengths and velocities. Related to the application, the simulations are executed for the button BPM arrangement as foreseen for the FAIR Proton LINAC. These investigations provide the required inputs for the BPM system and its related technical layout such as analogue bandwidth and signal processing electronics. For the BPM electronics, it is important to estimate the contribution of the harmonic used for the data processing. Additionally, the analogue bandwidth of the BPM system is determined from studying the output signal of the button BPM as a function of bunch length at different beam velocities. This contribution presents the results of the simulations and comments on general findings relevant for a BPM layout and the operation of a hadron LINAC.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG05  
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TUPG70 Test of the Imaging Properties of Inorganic Scintillation Screens Using Fast and Slow Extracted Ion Beams 516
  • A. Lieberwirth, P. Forck, O.K. Kester, S. Lederer, T. Sieber, B. Walasek-Höhne
    GSI, Darmstadt, Germany
  • W. Ensinger, S. Lederer, A. Lieberwirth
    TU Darmstadt, Darmstadt, Germany
  • P. Forck, O.K. Kester
    IAP, Frankfurt am Main, Germany
  Funding: Work supported by BMBF, contract number 05P12RDRBJ
Inorganic scintillation screens are a common transverse profile diagnostics tool for beams extracted from the heavy ion synchrotron SIS18 at GSI. Detailed investigations concerning light output, profile reproduction and spectral emission were performed for phosphor screens P43 and P46, single crystal YAG:Ce, alumina ceramics and Chromium-doped alumina (Chromox). The screens were irradiated with several ion species from proton to Uranium. The particle energy was 300 MeV/u at intensities in the range from some 106 to 1010 particles per pulse, using either fast extraction (1μsecond duration) or slow extraction (some 100 ms duration). The light output coincides for both extraction types, i.e. no significant saturation was observed. For all materials the optical emission spectrum is independent on the ion species or beam intensities. Radiation hardness tests were performed with up to 1012 accumulated ions: The phosphor P46 as well as YAG:Ce shows no significant decrease of light output, while for P43 and Chromox a decrease by 5 to 15 % was measured. These results will trigger the choice of the standard screens installed at the FAIR facility.
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG70  
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TUPG71 Ionization Profile Monitor Simulations - Status and Future Plans 520
  • M. Sapinski, P. Forck, T. Giacomini, R. Singh, S. Udrea, D.M. Vilsmeier
    GSI, Darmstadt, Germany
  • F. Belloni, J. Marroncle
    CEA/IRFU, Gif-sur-Yvette, France
  • B. Dehning, J.W. Storey
    CERN, Geneva, Switzerland
  • K. Satou
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • C.A. Thomas
    ESS, Lund, Sweden
  • R.M. Thurman-Keup
    Fermilab, Batavia, Illinois, USA
  • C.C. Wilcox, R.E. Williamson
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  Nonuniformities of the extraction fields, the velocity distribution of electrons from ionization processes and strong bunch fields are just a few of the effects affecting Ionization Profile Monitor measurements and operation. Careful analysis of these phenomena require specialized simulation programs. A handful of such codes has been written independently by various researchers over the recent years, showing an important demand for this type of study. In this paper we describe the available codes and discuss various approaches to Ionization Profile Monitor simulations. We propose benchmark conditions to compare these codes between themselves and we collect data from various devices to benchmark codes against the measurements. Finally we present a community effort with a goal to discuss the codes, exchange simulation results and to develop and maintain a new, common codebase.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG71  
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TUPG73 Preparatory Work for a Fluorescence Based Profile Monitor for an Electron Lens 528
  • S. Udrea, P. Forck
    GSI, Darmstadt, Germany
  • E. Barrios Diaz, O.R. Jones, P. Magagnin, G. Schneider, R. Veness
    CERN, Geneva, Switzerland
  • P. Forck, S. Udrea
    IAP, Frankfurt am Main, Germany
  • V. Tzoganis, C.P. Welsch, H.D. Zhang
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  Electron lenses (e-lens) have been proposed and used to mitigate several issues related to beam dynamics in high current synchrotrons. A hollow electron lens system is presently under development as part of the collimation upgrade for the high luminosity up-grade of LHC. Moreover, at GSI an electron lens system also is proposed for space charge compensation in the SIS-18 synchrotron to decrease the tune spread and allow for the high intensities at the future FAIR facility. For effective operation, a very precise alignment is necessary between the ion beam and the low energy electron beam. For the e-lens at CERN a beam diagnostics setup based on an intersecting gas sheet and the observation of beam induced fluorescence (BIF) is under development within a collaboration between CERN, Cockcroft Institute and GSI. In this paper we give an account of recent preparatory experiments performed at the Cockcroft Institute's gas curtain experimental setup with the aim to find the optimum way of distinguishing between the signals due to the low energy electron beam and the relativistic proton beam.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG73  
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