Author: Predonzani, M.
Paper Title Page
MOOC03 The Fermi@Elettra Cavity BPM System: Description and Commissioning Results 26
 
  • M. Ferianis, A.O. Borga, P. Craievich, R. De Monte, G. Gaio, M. Predonzani
    ELETTRA, Basovizza, Italy
  • M. Dal Forno
    DIEIT, Trieste, Italy
 
  The Fermi@elettra cavity BPM (C-BPM) system is based on an original implementation of the C-BPM scheme as the pick-up, operating at 6.5GHz, is coupled to a dedicated, self-calibrating electronics based on a novel concept. The system has been developed in-house; both the E-M and the mechanical design of the pick-up have been carried out, including an original frequency tuning scheme. The detector electronics directly obtains the envelope of the sum and difference signals by means of an RF 180° hybrid; no mixer for the RF signal down conversion is used. The detector is based on 3 blocks: an RF front-end, a baseband analogue transmission module and a digital back-end unit, based on a micro-TCA platform. The digital back-end is equipped with a powerful Virtex 5 FPGA and several real-time tasks have been implemented on it, including intra-pulse calibration. Ten C-BPM stations have been installed so far, fully integrated in the FERMI control System, enabling a real-time control of this key FEL diagnostics. Results on performances with beam are also presented; the scale factor of C-BPMs is obtained with beam, as two-axis micrometer translation stages have been installed.  
slides icon Slides MOOC03 [2.733 MB]  
 
TUPD14 Commissioning of the Cavity BPM for the FERMI@Elettra FEL Project 329
 
  • P. Craievich, T. Borden, A.O. Borga, R. De Monte, M. Ferianis, M. Predonzani
    ELETTRA, Basovizza, Italy
  • M. Dal Forno, R. Vescovo
    DIEIT, Trieste, Italy
 
  The cavity Beam Position Monitor (BPM) is a fundamental beam diagnostic device that allows the measurements of the electron beam trajectory in a non-destructively way and with sub-micron resolution. Ten cavity BPM systems have been installed along the undulators chain in the FERMI@Elettra FEL1 project. In this paper we discuss the installation, commissioning and performance of these cavity BPM systems. We have carried out preliminary operations during a pre-beam period, such as the alignment and fine tuning of the RF cavities under vacuum. During the commissioning each BPM has been calibrated by mechanically moving the support on which the BPM is mounted. We have estimated the single shot resolution in presence of beam jitter by reading the beam position synchronously over many electron bunches from three or more BPMs. The algorithms have been subsequently improved, and the results are described.  
poster icon Poster TUPD14 [0.460 MB]