| Paper |
Title |
Page |
| WEPLT072 |
Preliminary Design of the RF Systems for the SPIRAL 2 SC Linac
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2014 |
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- M. Di Giacomo, B. Ducoudret, J.F. Leyge
GANIL, Caen
- J.F. Denis, M. Desmons, M. Luong, A. Mosnier
CEA/DSM/DAPNIA, Gif-sur-Yvette
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In the SPIRAL 2 Linac, a 5 mA, CW , Deuteron beam is accelerated up to 40 MeV, through a normal conducting RFQ and 26 independent-phase SC quarter wave resonators, working at 88,05 MHz. Tube and solid state amplifiers derived from the standard FM transmitter modules are used while a new digital control system has been designed for the feed-back and feed-forward control system. The paper presents the power and low level systems for both the normal and superconducting cavities and results of simulations of the RF system in operating conditions.
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| WEPLT073 |
VDHL Design and Simulation of a Fast Beam Loss Interlock for TTF2
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2017 |
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- A. Hamdi
CEA/Saclay, Gif-sur-Yvette
- M. Luong
CEA/DSM/DAPNIA, Gif-sur-Yvette
- M. Werner
DESY, Hamburg
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The TTF2 fast beam loss interlock provides different modes of protection. Based on the differential beam charge monitoring over a macropulse, a pulse slice or bunch-by-bunch, the signal processing time should be as short as the bunch repetition period (110 ns). The signal delivered by the toroid-like inductive current transformer always shows an envelope droop due to its self-inductance to resistance ratio. When the macropulse length is comparable to this ratio, the charge of each bunch must be derived from the difference of the top to the bottom level on the signal. This necessity combined to the various protection modes leads to a digital implementation. All the processing functionalities are designed with VHDL for a Xilinx FPGA. Because the interlock involves other control signals in addition to the toroid signal with specific shapes, which cannot be easily reproduced for the design validation before the TTF2 completion, VHDL provides meanwhile the possibility for an exhaustive validation of the system with a software test bench including all timing information.
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| WEPLT077 |
DESIGN OF A FULL-CUSTOM ACCURATE I-Q MODULATOR
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2026 |
| |
- M. Luong, M. Desmons
CEA/DSM/DAPNIA, Gif-sur-Yvette
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The I-Q modulator is a key component in a digital Low Level RF (LLRF) system for amplitude and phase feedbacks. Its residual errors in offset or gain have a strong impact on the dynamic and accuracy of the feedback loops. For some frequencies, commercial I-Q modulators are available on the market. But even in that case, these components are usually designed for broadband communication purposes, and their performances in term of residual errors may not fit the strict requirements on the final amplitude and phase loop stability. Since LLRF systems for accelerators are typically narrow-banded, i.e. limited to few MHz, it is possible to achieve a high directivity and a very accurate coupling for hybrids, and an excellent matching for all subcomponents in a fully custom design. This approach guarantees the lowest residual errors for an I-Q modulator. The principle for the design and the process for the optimization are presented in this paper.
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