| Paper | Title | Page |
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THP068 |
Recent Developments for the Improved Bunch Arrival Time Monitors at FLASH and for the European XFEL | |
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| At today's free-electron lasers, pump-probe experiments and seeding schemes put high demands on the timing stability of electron bunches. At FLASH and the upcoming European XFEL a reliable and precise arrival time detection down to the femtosecond level has to cover a broad range of bunch charges, which may even change from 1 nC down to 20 pC within a bunch train. At FLASH, the new bunch arrival time monitor has to cope with the special operation mode where the MHz repetition rate bunch train is separated into two segments for FLASH1 and FLASH2 beam lines. Each of the two segments will exhibit individual timing jitter characteristics since they are generated from two different injector lasers and can be accelerated with individual energy gain settings. This operation mode places high demands on both, the hardware and the required servers for the bunch arrival time monitor, with regard to automated control and exception handling. In this paper, we describe the adapted electro-optical subsystem and show latest results from the newly implemented read-out electronics based on the MTCA.4 platform. | ||
| THP083 | Coherent Radiation Diagnostics for Longitudinal Bunch Characterization at European XFEL | 925 |
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| European XFEL comprises a 17.5 GeV linear accelerator for the generation of hard X-rays. Electron bunches from 20 pC to 1 nC will be produced with a length of a few ps in the RF gun and compressed by three orders of magnitude in three bunch compressor (BC) stages. European XFEL is designed to operate at 10 Hz delivering bunch trains with up to 2700 bunches separated by 222 ns. The high intra-bunch train repetition rate offers the unique possibility of stabilizing the machine with an intra-bunch train feedback, which puts in turn very high demand on fast longitudinal diagnostics. Two different systems will be installed in several positions of the machine. Five bunch compression monitors (BCM) will monitor the compression factor of each BC stage and used for intra-bunch train feedbacks. A THz spectrometer will be used to measure parasitically the longitudinal bunch profile after the energy collimator at 17.5 GeV beam energy. We will present concepts for fast longitudinal diagnostic for European XFEL based on coherent radiation, newest developments for high repetition rate measurements and simulations for the feedback capability of the system. | ||