| Paper |
Title |
Page |
| 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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| TUPB17 |
Diagnostics for the CTF3 Probe Beam Linac CALIFES
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99 |
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- W. Farabolini, D. Bogard, A. Brabant, A. Curtoni, P. Girardot, F. Gobin, R. Granelli, F. Harrault, C. L.H. Lahonde-Hamdoun, T. Lerch, M. Luong, A. Mosnier, F. Orsini, F. Peauger, C. Simon
CEA, Gif-sur-Yvette
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CALIFES is the probe beam linac developed by the CEA/DAPNIA and LAL in the frame of the CFT3 collaboration at CERN. Its objective is to "mimic" the main beam of CLIC in order to measure the performances of the 30 GHz CLIC accelerating structures. The requirements on the bunched electron beam in terms of emittance, energy spread and bunch-length are quite stringent and lead to use the most advanced techniques: laser triggered photo-injector, velocity bunching, RF pulse compression… In order to tune the machine and assess its performances before delivering the beam to the test stand a complete suit of diagnostics is foreseen including charge monitor, beam position and video profile monitors, deflecting cavity, RF pick-up and analysis dipole. All these diagnostics will be interfaced to the CERN command/control network. A special effort has been done on the Video Profile Monitors that make use of both scintillation and OTR (Optical Transition Radiation) screens and are fitted with 2 optical magnifications to fulfill field of view and resolution performances (<20μm). Their performances can be checked via an integrated resolution pattern.
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| WEPC19 |
Toroid Protection System for FLASH
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349 |
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- A. Hamdi, F. Ballester, M. Luong, J. Novo
CEA, Gif-sur-Yvette
- L. Froehlich, M. Görler, S. Magnus, M. Staack, M. Werner
DESY, Hamburg
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The FLASH fast machine protection includes a beam loss interlock using toroids to measure the beam charge. This system monitors the beam losses across the whole linac while other protection systems are specifically dedicated to critical components. Four protection modes are used to handle different scenarios of losses: charge validation, single bunch, slice and integration modes. This system is based on 4 ADC’s to sample the top and bottom of upstream and downstream toroid signals. A microcontroller drives 2 programmable delay generators to adjust the top and bottom ADC trigger during the calibration phase. The samples are then collected by a 200Kgates FPGA to process the various protection modes. At first, a VHDL testbench was developed to generate test vectors at the FPGA design inputs. Then, an electronic testbench simulates the linac signals to validate the global hardware functions. Finally, the toroid protection was tested on FLASH with long bunch train at 1 MHz repetition rate.
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