Keyword: GSI
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MOPC36 Test of a Non-Invasive Bunch Shape Monitor at GSI High Current LINAC electron, linac, longitudinal, MCP 151
 
  • P. Forck, C. Dorn, O.K. Kester, P. Kowina, B. Zwicker
    GSI, Darmstadt, Germany
  • O.K. Kester
    IAP, Frankfurt am Main, Germany
 
  Funding: The work is funded by European Union FP7 within CRISP.
At the heavy ion LINAC at GSI, a novel scheme of non-invasive Bunch Shape Monitor has been tested with several ion beams at 11.4 MeV/u. The monitor’s principle is based on the analysis of secondary electrons as liberated from the residual gas by the beam impact. These electrons are accelerated by an electrostatic field, transported through a sophisticated electrostatic energy analyzer and an RF-deflector, acting as a time-to-space converter. Finally a MCP amplifies electrons and with a CCD camera the electron distribution is detected. For the applied beam settings this Bunch Shape Monitor is able to obtain longitudinal profiles down to a width of 400 ps with a resolution of 50 ps, corresponding to 2 degree of the 108 MHz accelerating frequency. Systematic parameter studies for the device were performed to demonstrate the applicability and to determine its resolution. The achievements and ongoing improvements for the monitor are discussed.
 
poster icon Poster MOPC36 [2.665 MB]  
 
MOPF13 Transverse Beam Profiling for FAIR ion, IPM, OTR, UNILAC 232
 
  • M. Schwickert, C.A. Andre, F. Becker, P. Forck, T. Giacomini, E. Gütlich, T. Hoffmann, A. Lieberwirth, S. Löchner, A. Reiter, B. Voss, B. Walasek-Höhne, M. Witthaus
    GSI, Darmstadt, Germany
 
  The FAIR facility will provide intense primary beams of protons and heavy ions, or secondary beams of antiproton and rare isotopes. The operation includes fixed-target experiments or subsequent facilities of independent storage rings and experiment beam lines. The particle beams greatly differ in ion species, intensity, time structure, spot size and stopping power. Therefore, transverse beam profile measurements require a careful choice of detector type for each location in order to cope with the large dynamic range and operational demands. This contribution presents the actual status of FAIR detector developments for intercepting devices (SEM-Grids, Multi-Wire Proportional Chambers, Scintillating Screens) as well as non-intercepting Beam Induced Fluorescence Monitors and Ionization Profile Monitors. Recently, promising results were obtained with slow extracted heavy ion beams in measurements of optical transmission radiation emitted from thin metal foils. The boundaries for the application area are described and basic detector parameters are summarized.  
 
MOPF14 Scintillation Screen Response to Heavy Ion Impact ion, UNILAC, radiation, transverse 235
 
  • E. Gütlich, O.K. Kester
    IAP, Frankfurt am Main, Germany
  • P. Forck, O.K. Kester
    GSI, Darmstadt, Germany
 
  For quantitative transverse ion beam profile measurement, imaging properties of scintillation screens have been investigated for the working conditions of the GSI linear accelerator. In the ion energy range between 4.8 and 11.4 MeV/u the imaging properties of the screens are compared with profiles obtained using standard techniques like SEM grids and scraper. Detailed investigations with e.g. Calcium and Argon ion beams on various radiation-hard materials show that the measured beam profiles can differ from those measured with standard methods and depend on several beam and material parameters *. For the practical usage of scintillators, it is necessary to have predictions for the response of the scintillator to a given ion beam. An existing model for the light output of scintillators for single particle irradiation has been extended to include the effect of overlapping excitation tracks. To validate the model, dedicated measurements with well-defined Carbon and Titanium ion beams at 11.4 MeV/u have been carried out. To understand the mechanisms, the beam flux and the pulse length has been varied. The measured light yield is compared to the model calculations.
* E. Gütlich et al., “Scintillation screen studies for high dose ion beam applications”, IEEE Transactions on Nuclear Science, Vol. 59, No. 5, October 2012, pp. 2354 – 2359.
 
poster icon Poster MOPF14 [0.818 MB]  
 
MOPF24 Magnetic Materials for Current Transformers CERN, vacuum, impedance, damping 263
 
  • S. Aguilera, P. Odier, R. Ruffieux
    CERN, Geneva, Switzerland
 
  At CERN, the circulating beam current measurement is provided by two types of transformers, the Direct Current Current Transformers (DCCT) and the Fast Beam Current Transformers (FBCT). Each type of transformer requires different magnetic characteristics regarding parameters such as permeability, coercivity and shape of the magnetization curve. Each transformer is built based on toroidal cores of a magnetic material which gives these characteristics. For example, DCCTs consist of three cores, two for the measurement of the DC component and one for the AC component. In order to study the effect of changes in these parameters on the current transformers, several interesting raw materials based on their as-cast properties were selected with the annealing process used to tune their properties for the individual needs of each transformer. First annealing tests show that the magnetization curve, and therefore the permeability, of the material can be modified, opening the possibility for building and studying a variety of transformer cores.  
poster icon Poster MOPF24 [1.185 MB]  
 
TUPC46 Beam Loss Monitoring Study for SIS100@FAIR beam-losses, ion, simulation, SIS 485
 
  • V.S. Lavrik, L.H.J. Bozyk, O.K. Kester, A. Reiter
    GSI, Darmstadt, Germany
  • O.K. Kester, V.S. Lavrik
    IAP, Frankfurt am Main, Germany
 
  FAIR, the facility for antiproton and ion research, is a multi-disciplinary accelerator facility which will extend the existing GSI complex in Darmstadt, Germany. In the FAIR start version, the new synchrotron SIS100 will provide proton or heavy ion beams for a variety of experiments. The GSI synchrotron SIS18 will operate as injector for SIS100. The current study focuses on beam loss measurements for SIS18 and SIS100. The aim of this study is to find quantitative methods to measure beam losses around the machine, mainly SIS100, on an absolute scale. The contribution will present results of two pilot experiments carried out in the high-energy beam lines and at the SIS18 with Uranium ions in the energy range up to 900 MeV/u. In the first experiment the Uranium beam was totally stopped in a Copper target and the particle shower measured with LHC-type ionization chambers. In the second experiment, the beam was slowly excited in the SIS18 synchrotron to create controlled losses on a scraper which were monitored by the DC current transformer and beam loss monitors. Experimental data are compared against the predictions of Fluka simulations.  
poster icon Poster TUPC46 [5.404 MB]  
 
TUPF21 Response of Scintillating Screens to Fast and Slow Extracted Ion Beams ion, extraction, target, radiation 553
 
  • A. Lieberwirth, W. Ensinger
    TU Darmstadt, Darmstadt, Germany
  • P. Forck, B. Walasek-Höhne
    GSI, Darmstadt, Germany
 
  Funding: Funded by German Ministry of Science (BMBF), contract number 05P12RDRBJ
For the FAIR project, imaging properties of inorganic scintillators for high energetic heavy ion beams were studied. In order to investigate the characteristics of scintillation response and transverse beam profile, several experiments were conducted with slow (200 ms) and fast (1 μs) extracted 350 MeV/u Uranium beams from SIS18. The extracted particle number was varied between 105 and 109 particles per pulse for the irradiation of seven different scintillators: YAG:Ce-crystals with different qualities, pure and Cr-doped alumina as well as two phosphors P43 and P46. Additionally radiation resistance tests for all phosphor screens and the Cr-doped alumina screen were performed by irradiating with more than 700 pulses with 109 ions each. Linear response in scintillation light output as well as realistic statistical moments over the large range of ion intensities are presented for each material. Only minor changing in target response was observed after 45 minutes of permanent irradiation.
 
poster icon Poster TUPF21 [2.601 MB]