JACoW is a publisher in Geneva, Switzerland that publishes the proceedings of accelerator conferences held around the world by an international collaboration of editors.
TY - CONF AU - Walker, N. AU - Ayvazyan, V. AU - Branlard, J. AU - Pfeiffer, S. AU - Schmidt, Ch. ED - McIntosh, Peter ED - Burt, Graeme ED - Apsimon, Robert ED - Schaa, Volker R.W. TI - Beam-Transient-Based LLRF Voltage Signal Calibration for the European XFEL J2 - Proc. of LINAC2022, Liverpool, UK, 28 August-02 September 2022 CY - Liverpool, UK T2 - International Linear Accelerator Conference T3 - 31 LA - english AB - The European XFEL linac consists of 25 superconducting RF (SRF) stations. With the exception of the first station which is part of the injector, each station comprises 32 1.3-GHz SRF TESLA cavities, driven by a single 10-MW klystron. A sophisticated state-of-the-art low-level RF (LLRF) system maintains the complex vector sum of each RF station. Monitoring and maintaining the calibration of the cavity electric field (gradient) probe signals has proven critical in achieving the maximum energy performance and availability of the SRF linac. Since there are no dedicated diagnostics for cross-checking calibration of the LLRF system, a procedure has been implemented based on simultaneously measuring the beam transient in open-loop operation of all cavities. Based on methods originally developed at FLASH, the European XFEL procedure makes use of automation and the XFEL LLRF DAQ system to provide a robust and relatively fast (minutes) way of extracting the transient data, and is now routinely scheduled once per week. In this paper, we will report on the background, implementation, analysis methods, typical results, and their subsequent application for machine operation. PB - JACoW Publishing CP - Geneva, Switzerland SP - 80 EP - 82 KW - cavity KW - FEL KW - LLRF KW - linac KW - operation DA - 2022/09 PY - 2022 SN - 2226-0366 SN - 978-3-95450-215-8 DO - doi:10.18429/JACoW-LINAC2022-MOPOPA03 UR - https://jacow.org/linac2022/papers/mopopa03.pdf ER -