Speaker
Description
PSI is investigating a SwissFEL extension with a new hard X-ray beamline, Porthos, in addition to the existing hard X-ray (Aramis) and soft X-ray (Athos) beamlines. To allow all three beam lines to operate simultaneously at the maximum RF pulse repetition rate (100 Hz), three bunches must be accelerated in each RF pulse. The three bunches will be separated by 21 ns. The accelerating voltages and phases for the three bunches need to be independently adjustable to tune the FEL properties. This poses significant challenges for the LLRF system, especially at RF stations equipped with pulse compressors. To make the three-bunch operation feasible, the machine layout has been updated by introducing a dedicated bunch compressor for the Athos beamline. In this work, an acceleration model for the traveling-wave structures is developed, allowing the accelerating voltages and phases for all bunches to be simulated for arbitrary pulse shapes. We performed a start-to-end co-simulation including all RF stations and the tracking of all bunches, serving as a virtual machine based on the actual RF operation parameters of SwissFEL. This model allows us to simulate the control methods, including the tuning knobs for all bunches and the beam-based longitudinal feedback loops. This contribution presents the modeling and simulation results mentioned above.
| Abstract Classification | Control Loop Modeling, Tuning and Optimization |
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