Echevarria, P.; Neumann, A.; Ushakov, A.; Knobloch, J.; Aldekoa, E.; Jugo, J.: Virtual SRF Cavity: Testing SRF Cavity Support Systems Without the Hassle of Liquid Helium and Klystrons. In: Peter Michel ... [Ed.] : SRF2019, Proceedings of the 19th International Conference on RF Superconductivity, Dresden, GermanyGeneve: JaCoW, 2019. - ISBN 978-3-95450-211-0, p. WETEB4/772-777
http://accelconf.web.cern.ch/AccelConf/srf2019/papers/weteb4.pdf
Open Access Version
Abstract:
Setting up and debugging SRF support systems, such as LLRF control, quench detection, microphonics and Lorentz- force detuning control, etc., often requires extensive time spent operating the cavities. This results in time consuming and costly operation. Early into the development stages the actual cavity system may not even be available. It is therefore highly desirable to pre-evaluate these systems under realistic conditions prior to final testing with the SRF cavities. We devised an FPGA-based "virtual cavity" that takes a regular low-level RF input and generates the signals for RF-power reflection, transmission and detuning that mimic the response of a real cavity system. As far as the user is concerned, the response is the same as for a real cavity. This "black-box" model includes mechanical modes, Lorentz force detuning, a field depended quality factor, quenches and variable input coupling and is currently being expanded. We present the model and show some applications for operating the quench detection, LLRF and microphonics control for 1.3 GHz bERLinPro cavities. The same system can be used for other cavity types, including normal conducting cavities.