|Beam Position Monitor using a re-entrant cavity|
|C. Simon, M. Luong, S. Chel, P. Contrepois, P. Girardot, CEA-Saclay, Gif sur Yvette, France N. Baboi, DESY, Hamburg, Germany N. Rouvière, CNRS-IN2P3-IPN, Orsay, France|
Two designs of high resolution beam position monitor, based on a radiofrequency re-entrant cavity, are developed at CEA/Saclay. 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 get a high resolution with the possibility to perform bunch to bunch measurements. Two prototypes with a large aperture (78 mm) are installed in the Free electron LASer in Hamburg (FLASH), 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 Clic Test Facility (CTF3) probe beam CALIFES at CERN. It is operated in single bunch and multi-bunches modes. This paper presents the mechanical and signal processing designs of both systems. Simulation and experimental results will be discussed.