| Paper |
Title |
Page |
| TUPB12 |
BPMs for the XFEL Cryo module
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84 |
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- D. Nölle, N. Baboi, K. Knaack, D. Lipka, J. Lund-Nielsen, N. Mildner, R. Neumann, F. Schmidt-Föhre, M. Siemens, T. Traber, S. Vilcins
DESY, Hamburg
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The European XFEL is based on superconducting accelerator technology developed in the context of the TESLA collaboration. The accelerator itself consist of cryo modules each equipped with 8 cavities, followed by a quadrupole/steerer package, a BPM and a HOM absorber. This contribution will present the layout of the BPM system for the cryo modules, describing the monitor itself, its integration into the cryo module. Additionally, the electronics concept will be discussed. Finally the results of beam measurements at FLASH using prototypes of the monitor and the electronics will be presented.
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| TUPB15 |
Beam Position Monitors Using a Re-entrant Cavity
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93 |
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- C. Simon, S. Chel, P. Contrepois, P. Girardot, M. Luong
CEA, Gif-sur-Yvette
- N. Baboi
DESY, Hamburg
- N. Rouvière
IPN, Orsay
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Two designs of high resolution beam position monitor, based on a radiofrequency re-entrant cavity, are developed at CEA/Saclay. The main radio-frequency modes excited by the beam in the cavity are monopole and dipole modes. The first monitor is developed in the framework of the European CARE/SRF program. It is designed to work at cryogenic temperature, in a clean environment and to get a high resolution and the possibility to perform bunch to bunch measurements. Two prototypes with a large aperture (78 mm) are installed in the FLASH linac, at DESY. The other design with an aperture of 18 mm and a large frequency separation between monopole and dipole modes, as well as a low loop exposure to the electric fields is developed for the CTF3 probe beam CALIFES at CERN. It is operated in single bunch and multi-bunches. This paper presents the mechanical and signal processing designs of both systems. Simulation and experimental results will be discussed.
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| TUPC26 |
Button Beam Position Monitors for FLASH
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201 |
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- J. Lund-Nielsen, N. Baboi
DESY, Hamburg
- W. Riesch
DESY Zeuthen, Zeuthen
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Abstract: FLASH (Free Electron Laser in Hamburg) accelerates electron bunches to up to 750 MeV for producing intense, coherent, very short pulses of radiation. Various types of BPMs (beam position monitors) are installed in the facility: cavity and re-entrant-cavity BPMs in the accelerating cryo-modules and button and stripline BPMs in most of the room-temperature sections. The undulator section, where the FEL radiation is produced, is one of the most critical areas of the linac in terms of requirements on the position monitoring. Due to the tight space, button BPMs were chosen for this area. The electronics is based on the AM/PM principle. In the past couple of years these BPMs were commissioned and intensively studied. A few modifications have been made in the electronics, in order to deal with the small signals and the very high frequencies of the ultra-short bunches. In this paper the button-BPMs at FLASH will be presented. The studies made in the RF laboratory and the measurements made on the performance of the BPMs will be discussed.
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