Author: Satou, K.
Paper Title Page
TUBO04 Measuring the Beam Profile by Counting Ionization Electrons 252
 
  • H.S. Sandberg, W. Bertsche
    UMAN, Manchester, United Kingdom
  • D. Bodart, B. Dehning, S. Levasseur, H.S. Sandberg, G. Schneider, J.W. Storey, R. Veness
    CERN, Geneva, Switzerland
  • S.M. Gibson
    Royal Holloway, University of London, Surrey, United Kingdom
  • K. Satou
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
 
  The principle of non-destructive beam profile measurement with rest gas ionization electrons has remained largely unchanged since the technique was first proposed in the late 1960’s. Ionization electrons (or ions) are transported by an electrostatic field onto an imaging detector, where the spatial distribution of detected electrons is a direct measure of the transverse beam profile. The detector typically consists of one or more Micro-Channel Plates (MCP’s) to amplify the signal, followed by either a phosphor screen and camera, or pickup electrodes. A long-standing problem is the ageing of the MCP’s, which limits the accuracy of the beam profile measurement. A new technique to detect ionization electrons has been developed at CERN, which uses a hybrid pixel detector to detect single ionisation electrons. This allows the application of counting statistics to the beam profile measurement. It will be shown that a meaningful beam profile can be extracted from only 100 electrons. Results from the new instrument will be presented, which demonstrate the ability to measure the beam profile of single bunches turn-by-turn, which offers new opportunities for beam diagnostic insights.  
slides icon Slides TUBO04 [2.199 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUBO04  
About • paper received ※ 03 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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TUPP020 Development of a Gated IPM System for J-PARC MR 338
 
  • K. Satou
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
 
  In the Main Ring (MR) of Japan Proton Accelerator Research Complex (J-PARC), a residual-gas ionization profile monitor (IPM) is used to measure bunched beam profiles. After injection, the beam widths of the first ~20 bunched beams are analysed to correct the Quadruple oscillation. While only a few dozen profiles are required for this correction, the present IPM auto-matically measures all bunched beams, more than 2·106 bunches from injection to the extraction, because the present IPM operates using DC. This system is unde-sirable due to the limited lifetime of the Micro Channel Plate (MCP) detector; the more particles the MCP senses, the more it loses gain flatness and thus lifetime. To improve this situation, a gated IPM system has been developed, in which the High Voltage (HV) is operated in pulse mode. Results of performance analysis of a new HV power supply, improvement of the electrodes, and particle-tracking simulation considering the space-charge-electric field of the bunched beam are de-scribed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP020  
About • paper received ※ 04 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)