Keyword: alignment
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MOPD15 Electromagnetic Simulations of an Embedded BPM in Collimator Jaws simulation, pick-up, collimation, proton 71
 
  • A.A. Nosych, C.B. Boccard, M. Gasior
    CERN, Geneva, Switzerland
 
  Next generation of the LHC collimators will be equipped with button beam position monitors (BPMs) embedded into the collimator jaws. Such a solution will improve the accuracy of the jaw alignment with respect to the beam and reduce the beam time necessary for the collimator setup. This paper describes results of electromagnetic simulations of the jaw BPMs performed with the CST Particle Studio suite, aimed at characterisation of the BPMs as well as the simulation software itself. The results are compared to the measurements obtained with beam on a prototype system installed in the CERN SPS.  
poster icon Poster MOPD15 [6.439 MB]  
 
MOPD57 Quantitative Scintillation Screen Studies at GSI-LINAC and Related Model Calculations ion, linac, emittance, target 179
 
  • E. Gütlich, P. Forck, B. Walasek-Höhne
    GSI, Darmstadt, Germany
  • W. Ensinger
    TU Darmstadt, Darmstadt, Germany
 
  Scintillating screens are commonly used at accelerator facilities, however their imaging quality are not well understood, especially for high current ion beam operation. Several types of inorganic scintillators were investigated for various ion species and energies between 4.8 and 11.4 MeV/u. To validate the imaging quality of the scintillators a scraper scan method was established. For Al2O3 with a Ca beam of 4.8 and 11.4 MeV/u and a constant beam flux (ions/cm²/s), these methods are compared. For 4.8 MeV/u the results are in good agreement, while for 11.4 MeV/u the screen image does not reflect the beam distribution. A microscopic model is under development taking the properties of the fast electrons generated by the primary interaction into account. For Al2O3 this model can describe the observed saturation effect. Spectroscopic investigations were performed, to determine the influence of the ion beam intensity on the luminescence spectra emitted by the materials. No significant dependence on the spectrum with respect to the beam intensity was found for most of the scintillators.  
 
MOPD59 A New Fast Acquisition Profile for the LHC and the SPS radiation, optics, betatron, injection 182
 
  • S. Burger, A. Boccardi, E. Bravin, A. Rabiller, R.S. Sautier
    CERN, Geneva, Switzerland
 
  The beam profile is an important parameter for the tuning of particle accelerators. These profiles are often obtained by imaging optical transition radiation from a radiator on a CCD camera. This technique works well for slow acquisitions, but in some cases it is necessary to acquire profiles with higher rates where such standard cameras are no longer suitable. In our case the aim is to sample the profiles on a turn-by-turn basis which, for the CERN-SPS, corresponds to ~44 kHz. For this reason we have developed a fast detector based on a recent Hamamatsu linear CCD and an optical system using cylindrical lenses. The readout electronics is based on CERN developed, radiation tolerant components and the digital data is transmitted to an acquisition board outside of the tunnel by mean of optical fibres. This contribution describes the system and shows the performance obtained on a test bench.  
 
TUPD49 Performance of Parabolic and Diffusive OTR Screens at the CLIC Test Facility 3 dipole, linac, diagnostics, simulation 413
 
  • M. Olvegård, B. Bolzon, E. Bravin, S. Burger, A.E. Dabrowski, T. Lefèvre
    CERN, Geneva, Switzerland
  • C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
 
  At the CLIC Test Facility 3, OTR screens are commonly used in beam imaging systems for energy and energy spread characterization in dedicated spectrometer lines. In these lines the horizontal beam size is typically of the order of one centimeter. Already in 2005 a limitation was observed resulting from a strong dependence of the intensity of the light captured by the camera, on the position on the screen (vignetting). The severity of this effect increases with the electron energy, as the aperture of the optical system is finite and the OTR photons are emitted in a small cone of 1/γ angle. To mitigate this effect, different shapes and surface polishing of the screens were investigated. Parabolic and diffusive OTR radiators were tested in several spectrometer lines all along the CTF3 complex. The results are presented in this paper.  
 
TUPD83 Photodiode Calibration using an Electrical Substitution Radiometer in the Hard X-ray Region simulation, photon, radiation, cryogenics 500
 
  • N.I. Bolibruch, R. Igarashi, J.M. Vogt
    CLS, Saskatoon, Saskatchewan, Canada
 
  Funding: Work supported by NSERC, NRC, CIHR, WEDC.
An electrical substitution radiometer under development at the Canadian Light Source (CLS) has been used to calibrate a photodiode (AXUV100) from International Radiation Detectors Inc. within an energy range of 8 keV to 30 keV. These measurements were made using monochromatic X-rays on the Biomedical Imaging and Therapy bend magnet beam line and the Hard X-Ray Microanalysis beam line at the CLS. The results were then compared with silicon absorption calculations using data from the NIST mass absorption coefficient tables. Good agreement has been found between the diode calibration obtained from the radiometer and the theoretical calculation of the diode response.