Author: Lipka, D.
Paper Title Page
WEAO02 Pile-Up Effect of Cold Button BPMs in the European XFEL Accelerator 450
 
  • D. Lipka, B. Lorbeer
    DESY, Hamburg, Germany
 
  The European XFEL facility is in operation with a maximum of 2700 bunches in one train. The highest bunch repetition rate is 4.5 MHz; this corresponds to a minimum time separation of 222 ns. The measurement of the beam properties for each bunch in a train is required. Therefore the beam position monitor (BPM) system needs to separate the signals from each bunch. All BPM types (button, re-entrant and cavity) fulfill this requirement except a few button BPMs installed inside of the cold accelerator module, where Pile-Up from the train can be observed. To identify the cause of this effect we measured the S-parameters during a shutdown of the accelerator, compared it with a similar BPM at the FLASH accelerator but located in a warm section and finally measured the spectrum of the button signal during beam operation. As a result, resonances were found at about 2.46 GHz with relatively high quality factor that remains within the frequency range accepted by the electronics.  
slides icon Slides WEAO02 [5.621 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WEAO02  
About • paper received ※ 04 September 2019       paper accepted ※ 09 September 2019       issue date ※ 10 November 2019  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPP015 ESS Beam Position and Phase Monitor System 536
 
  • R.A. Baron, H. Hassanzadegan, A. Jansson, H. Kocevar, K.E. Rosengren, T.J. Shea
    ESS, Lund, Sweden
  • I. Bustinduy, S. Varnasseri
    ESS Bilbao, LEIOA, Spain
  • F. Grespan, M. Poggi
    INFN/LNL, Legnaro (PD), Italy
  • T. Gräber
    DESY Zeuthen, Zeuthen, Germany
  • D. Lipka, S. Vilcins
    DESY, Hamburg, Germany
 
  The European Spallation Source (ESS) is a neutron facility under construction in Lund, Sweden, and established as an European collaboration between different member countries. The machine is a 2 GeV proton LINAC with a nominal beam current of 62.5 mA, 2.86 ms of pulse length and a bunch repetition rate of 352 MHz. The Beam Position and Phase Monitors (BPM) at ESS were designed to satisfy the specifications for the different beam modes, which span from 5 µs pulse length and 6.3 mA beam until the nominal beam condition. The system is designed for standard beam position measurements for beam trajectory correction and for beam phase measurements for cavity phase tuning, imposing restrictions on the sensor design and electronics architecture. Approximately a hundred BPM’s were manufactured and are being installed by partners in collaboration with ESS. The BPM system comprises a MicroTCA.4 electronics based in COTS AMC and RTM modules with custom FPGA firmware implementation and a custom Front-End electronics. In this work, the system architecture, implementation, performance, and test results are presented and discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WEPP015  
About • paper received ※ 04 September 2019       paper accepted ※ 09 September 2019       issue date ※ 10 November 2019  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)