Author: Nosych, A.A.
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MOPF10 A Compact In-Air X-Ray Detector for Vertical Beam Size Measurement at ALBA 69
 
  • A.A. Nosych, U. Iriso
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
 
  An in-air x-ray detector (IXD) was developed for ALBA to study the residual x-rays after traversing the 35mm copper crotch absorbers. The device prototype is placed in-air after such absorber, mounted flush with the vacuum pipe. The remaining x-rays (above 120 keV) generate a visible footprint if they impinge upon a sensitive enough scintillator. We are using a Cerium doped PreLude 420 (LuYSiO:Ce) screen, and the image is observed with a simple optics system mounted on a commercial CCD camera. This measurement allows evaluating the vertical electron beam size with exposure times in the order of seconds. Similar instruments are used at ESRF and ANKA storage rings. This paper presents the results of the first measurements with IXD and describes its potential to be used as a full diagnostics tool for the 3 GeV storage ring of ALBA.  
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TUPF03 Overview of the Geometrical Non-Linear Effects of Button BPMs and Methodology for Their Efficient Suppression 298
 
  • A.A. Nosych, U. Iriso, A. Olmos
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  • M. Wendt
    CERN, Geneva, Switzerland
 
  This paper describes an overview of the geometric non-linear effects common to beam position monitors (BPMs) installed in the accelerators and a methodology to correct for these effects. A typical characteristic curve of a pick-up is linear within a limited range from the BPM origin. At larger offsets the non-linearity of the curve is more pronounced and gets worse if the button diameter is small with respect to the beam pipe diameter. The general real-time linearization methods usually utilize linear correction combined with a simplistic polynomial, which may lead to inaccuracies in their limited application. We have developed a more rigorous methodology to suppress the non-linear effects of the BPMs through electromagnetic (EM) simulations and 2D fitting approximations. The focus is mainly on standard button pick-ups for the electron (ALBA) and proton machines (LHC).  
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